You're right, there should be a wiki... there isn't. Lots of good stuff on the Campy-only site, but it's dated. There's some good info on the Branford Bike (knowledge base) website, but again... not all that well maintained.

The Paceline is a good forum, especially due to having "oldpotatoe" there to answer specific Campy questions. Another good source is Graeme from Velotec UK, I think he's on this forum, as well as several others.

As for a good wiki/library type of thing that's up to date, you're out of luck.

Compatibility across Campagnolo lines can be a real headache and head-scratcher, which may be part of the problem. As long as you stay at the Chorus/Record level, parts are compatible across the ten speed line that spanned the 2000s. There is also compatibility with some 9 speed stuff that was produced later, but the early 9 speed campy stuff is incompatible with 10speed. It gets more confusing when you go down into the lower tiers (starting in 2007, prior to that, things were basically compatible across the board).

In 2007, Campy messed with the front shifting and changed the geometry of the front derailleur on Centaur and down. At this point, Centaur inherited the much maligned "Escape" mechanism in the shifter.
In 2009, a new generation of shifters was released. All of the ten speed components at that time are compatible. Whether or not the ten and eleven speed components are fully compatible has been debated a good bit (at least as far as the rear derailleur is concerned; some claim it works, others disagree).
In 2011, Athena/Centaur/Veloce got down-graded and lost Ultra-torque cranksets and lost Ultra-shift (ability to shift across the cassette in one stroke). The replacement Power-torque and Power-shift were definitely a step backwards, but not the end of the world or any serious reduction in quality.
In 2015, Campy completely changes the geometry of the 11speed line which is no longer compatible with older Campy 11 speed.

For the most part, Campy 9/10/11 speed are compatible but there are just so many exceptions that I hesitate to say that. At least the wheels are compatible, the older 8 speed hubs are completely different.

Cranksets aren't a big deal, you can get away with a 10speed crank on an 11speed system or vice versa.
You can find a wider cassette, maybe something like a 13-29 but campy cassettes are pricey. Best to order from Ribble or another overseas vendor if you are in the US.
If you really need more gear, grab a NOS triple or something with arms for a 74bcd ring... doesn't have to be made by Campy.

Might as well pick up some g-springs and a carrier while you are at it, and rebuild your shifters! Good news, Record 10 can be rebuilt; bad news, sometimes it needs to be rebuilt. The newer style ergos (starting in 2009) lack this ability.