I'll get the easy one out of the way...Pilot isn't listed as one of the generic keywords in the latest rulebook, so it's non-generic, yes? Sulu has the keyword from the Away Team pack.

Now, I could've sworn there was discussion about a limitation to the "sideboard" you can bring that consists of characters you want to split/merge into and/or alter ego into.

Now, I've got a team with:

Ant-Man & Wasp
Rick Jones
Donald Blake

Can I bring along all 3 possible Thors for Blake, all 3 possible incarnations for Jones (A-Bomb, Cap'n Marvel, Genis-Vell), and a multitude of Ant-Men & Wasps to split/merge with, all sitting on their KO clicks off to the side of the gaming board?

There's no specific limit mentioned under REPLACING CHARACTERS on page 6 other than "All players should agree on the maximum number of replacement characters per force"...

Since it is not on the list, Pilot would be a named keyword.

As you quoted, the limitation to number of characters on the sideboard is agreed upon by the players. For a tournament, this would actually be decided by the judge.

No official number is given in the documentation, but a Rule Deputy has stated that it is 2 characters per 100 points of the build total, if I remember correctly. I'll try to find the post, and link it here.

edit: vlad helpfully provides an answer in post 7. I was right, 2 characters per 100 points, but he also says a hard cap of 12.

It all comes down to what your venue would allow in a tornament, or what your opponent and you decide before the game in a friendly game. The rules say you can, but they also say that limitations on how many sideboard character you can bring in a game can be put.
An example : in a tornament the judge say that you cannot bring more than 200 points worth of character on the sideboard. You would have to come with less than 200 points of Thors, Wasps, Captain Marvel etc. If all the above are les than 200 point then yes, you would come with all your stuff. If not you would have to make choices.
Other limitations might exist ("no more than X characters no matter the cost", "only AEs", etc.)
There are no standard rules thu.

The default tournament build is 300 points. Nobody really feels bound by that fact, it's almost more a trivia question. The sideboard limits are meant to be treated similarly. 2/100 cap 12 is what WK considers a useful general default. Your venue is free to establish it's own default, or change the numbers as often as it changes tournament build totals.

Thanks, all.

Just a quick update. The new Comprehensive Tournament Rules upped the sideboard by a little bit:

2.6 Replacement Characters: Whatever replacement character policy the event will use should be available in the event description. The default replacement character limitiation is 3 per 100 points of the build total, with a maximum of 15 replacement characters per force.

Interesting. Other than Duo's split/merge options being limited, this doesn't seem like much of a cap. Seems to me that most teams would never even come close to hitting that number.

There are 28 figures named "Batman", not counting various random "Bruce Wayne" figures not named Batman. There are 12 figures named "Robin". That's a lot of options for splitting the Batman and Robin duo figure and I can see some idiot bringing them all with him just because he can. Well, he can't now!

I only want to play B&B duos with all their possible replacements and keep changing one for the other like a madman. That would make a few sideboard character too. You can also bring your Pym, your Beast Boy, Batman & Robin, Green Lantern & Green Arrow, Superman & the Flash. You got your fifteen right there.

Also more and more AEs are able to turn into multiple characters these days.

If I play a team of 6 Rick Jones characters (and, yes, I seriously want to do this... I need two more Ricks, though), and I wanted to make sure each Rick had all three options available to him to turn into, I'd have a sideboard with 18 characters (6 A-Bombs, 6 Mar-Vells, 6 Genis-Vells), That'd be a no-no.

i'm glad no one at my venues uses Duos ever...

Fair points. I guess I don't play AEs or Duos often enough. Hell, I don't play HeroClix often enough. If I did, I would probably try this more often now that the options are better for such things.