Yep! It's definitely a good thing to give characters something to say about everything (almost). As you say, it fleshes them out - you stop thinking of them as "two-dimensional hand-drawn faces" and start thinking of them as "real people".
It's cool that this game sparked your interest in N'Awrlins, and even cooler that you got to visit.
Personally -- Alas, I've never been to America. The more I read about America, the more I realise it has so many great sites to see -- but I only have a limited budget. *shrug* Oh well. Perhaps some day.
I just finished reading a book about the Wild West. It describes the West in such vivid colours, I thought I'd love to see Yosemite and Yellowstone National Parks -- and walk through them, take them in, not just 'here's Fairy Falls - now let's rush or we'll miss Old Faithful' etc. If I see Old Faithful erupt, I'll see it. If not, I won't. It's nature, not a theme park ride.
What else would I like to see? Tombstone, Arizona. Dodge City, Kansas. Silverton, Colorado. Deadwood, South Dakota. I don't imagine for a minute that they would look like they did back in the Wild West, but hey - time moves on.
Oh, whoops. I'm rambling. Sorry. *blush*
==============
A world without the internet? Watchu talkin' 'bout, Willis?
'Tis true. Back in the days of dial-up modems, we weren't *makes quotemarks with fingers* "surfin' the web" with graphical user interface and pretty pictures. It was all TEXT! *sulks* An' we LIKED it that way.
==============
Yep, the story, the art, the voices are GREAT. Here's something you may not have known (I certainly didn't): Tim Curry also voiced the Gedde Estate Butler.
And yes, Virginia Capers was the narrator. Leilani Jones voiced Malia Gedde. Desk Officer Frick was voiced by Jim Cummings (who also did a bunch of other voices, e.g. Gunther and the Dragon). Grandma Knight is voiced by Linda Taylor (who also voices Tetelo).
Another fun fact: Jim Cummings (aka Desk Officer Frick, and others), worked in New Orleans as a designer of Mardi Gras floats, a singer, a door-to-door salesman, and a Louisiana riverboat deckhand. After that, he moved to Anaheim, CA, where he became a voice actor. (Thanks, IMDB!)
Spoiler alert: just because Dr John knows a lot about voodoo, doesn't mean he's heavily involved in the voodoo cult.
==============
By the way:
"Goat without horns" makes sense as
a human sacrifice. Goats were
often used in both cults and religions as sacrifices, so having a goat
without horns makes sense.
==============
I just noticed something. When Gabe turns out the heat in the office, Mosely is so bothered that he takes off his jacket. But Gabe still has his leather jacket on. Wouldn't he be boiling?
Leather jackets are
warm. (I own one, so I know).
==============
Here's how to figure out the clock business:
The Dragon symbol is significant to the Gabriel family.
As for the time on the clock - what number is significant to the Gabriel family?
Have you looked at your father's painting?
Have you translated Heinz Ritter's poem?
Have you looked at the sketch book?
Three snakes, three dragons ... three o'clock.
==============
Incidentally, I love the picture of Gabriel as priest. He looks so ... wholesome. And, of course, the blessing over the amulet that Madame Cazanoux gives you.
"Bless it, Wilbur!" 
It's such a Gabriel Knight thing to say. Is he asking the guy from Mr Ed to bless the amulet?
==============
Uh, it's an alligator head. Crocs (or crocodiles) live in freshwater areas OR saltwater ones, but alligators can only live in freshwater areas (e.g. swamps, marshland, rivers, lakes). So, seeing as New Orleans has a substantial and extensive swamp ... the bayou ... watch out for alligators.
There are many differences between crocs and alligators: alligators live only in many of the southern US states, as well as the north of South America. Crocodiles can also live in (most of) Africa, the northeast of Australia, and much of southeast Asia (e.g. Thailand, Vietnam, Papua New Guinea etc.)
The alligator snout is broad, and shaped like a U. The crocodile snout is narrower, and shaped like a V.
Also, American alligators are mostly green; crocodiles can be brown. There are other differences too -
here. (I did a lot of research on crocs and alligators when I included one or two in a story).
==============
Hold on, Crash is poisoned? I thought the game said that
his neck showed signs of strangulation. *shrug* It depends on the poison, of course, but some poisons are slow and allow you to talk to the victim. Strangulation is far quicker. (I'm not trying to be creepy or anything, it's just a medical fact). His face is also unnaturally purple, which indicates strangulation. But there's no-one near him, so who strangles him?
It is, of course, very possible that he is fed something - something poisonous? - by the rada drummer that he talks to. Some poisons - very nasty ones - can deprive a human being of oxygen, but they are usually very quick. Cyanide is a famous example; if you have no protection, any kind of cyanide can kill within three or four seconds. 
But cyanide has a use in heavy industry, as well as crash repair. You just need a lot of the right protection.
==============
As for the cult building their base underneath the cathedral - what makes you think the priests KNOW that the cult base is there? This cult is well-connected, has a LOT of money, and (if Malia Gedde is any indication) is well-respected in high society. Even if the priests suspected something, who would they go to?
Yes, the "well-connected members of high society who are secretly plotting to do XYZ" is a bit of a stereotype - but it's a stereotype because it's happened so many times.
The various orders of Crusader knights, for instance (e.g. the Templars, the Hospitallers etc.) were well-connected to high-ranking nobles and even kings. As well as being knights, they were also merchants, bankers, and moneylenders (even to kings). The Templars were eventually disbanded because the King of France at the time owed them a lot of money and couldn't afford to pay, so he accused them of witchcraft and heresy and so on. (That's the basis of Gabriel Knight 3).
To come back to
the cult base underneath the cathedral... Isn't it a great irony? It's the last place you'd expect them to be. And maybe they figured - hey, as long as we're here, let's be comfortable. So they used their pots-of-money to do some building and stuff.
Maybe
they subcontracted the base-building to a bunch of tradesmen, who built the thing - and then they murdered them. "Now that you know, you will not leave." 
Sure, it could've been a cave or caves, but then it would be like "The Elder Scrolls 4: Oblivion" and other fantasy games.
Besides, it's a game where Gabriel has a vision of a dragon. The dragon
burns away the selfish part of Gabriel. Also,
zombies come back to life. And the
cult base is the MOST unrealistic thing?
==============
The library thing ... yeah, in a story, this is called "an info-dump" - because you basically dump a whole bunch of info on the player (or the reader).
An info-dump is important to move the story forward, but it's important to do it in the right way and at the right time. NEVER, NEVER do an info-dump right at the beginning, because no-one will care.
Imagine you haven't even started a game, and they give you all this info about such-and-such and so-and-so. Who cares?
I think they handled the info-dump just right: it wasn't one book that gave you all this info, but five books that introduced a very important (and complicated) subject in stages, so it kept your interest.
But just imagine if it was one book, and a WHOLE bunch'a info ... both you and Gabe would've thought, "I HAVE TO READ ALL THIS?!"
==============
Ah, yes ... day 9. Easily the hardest (and most horrifying) part of the game. Have fun playing zombie dodgem.
But once you get past the zombies ...
Incidentally, Wolfgang is Gabe's uncle. (Yep. He's the brother of Gabe's father. Gabe's gran tells you so at the beginning.
He's played by
Efrem Zimbalist, Jr., a great actor).
Oh, and
here's the guy who played Dr. John - don't they look similar? (I said similar, not the same).
And ...... ugggghghghgh!!! :devil: Wolfgang's sacrifice scene is so damn powerful.
A tear-jerker scene for sure.
==============
Aha! It's day 10. The worst is over.
I like the savegame where you get all the money. "Well Well Well". "XtraCash".
Um, the money isn't counterfeit. It's real enough. Gabe wouldn't take it if it was fake.
It's money that the cult stashed away over the years - stolen from victims, gotten from bequests and so on ... you're thinking "Bequests? Who would bequest money to a bunch of crazy killers?" but you're forgetting that this cult has a life above-ground, where they are respectable members of high society.
Um ... the goddess that Malia sacrifices herself to stop is
Tetelo, not Toledo.
Toledo is a town in Ohio (and also in Spain - Toledo steel is very famous).
What, you didn't include the
OTHER ending? Aww.
Thanks, Tawm! That was fun.
*presses "Delete"*