1. Where will these mods be hosted, and by whom?
2. What is the method of distribution for these mods?
3. Who is responsible for the content of these mods? And who decides if any of these mods conforms to a proper criteria that allows them to be hosted?
4. Who decides the criteria for acceptability? How are the copyright issues to be handled?
5. How does a modder have his/her mod added to this list of mods in the distribution forum?
6. Who "owns" the modded content?
7. How do mods that are distributed elsewhere (like CFC, or Apolyton) fit into this modding strategy? Is there a different procedure for using those mods in the game?
Most of your questions have already been answered:
1. Steamworks obviously.
2. Duh... the internet eh?

3. 2K (job advert on Gamasutra a few months ago)
4. 2K, and I'm sure copyright issues are handled by your mod not being hosted.
5. You upload it (numerous reviews from PAX and E3).
6. 2K (if the EULA is the same as any other game every written).
7. Process is the same as Civ4 (Dennis Shirk @ PAX).
And some other mod based questions that have been asked:
1. Will there be an SDK for Civ5? Or some other type of release of core game code that modders can access?
2. It has been mentioned that the new modding system will use Lua as a scripting language. Is this true?
3. Will there be any other languages supported for the use of modders? XML has been pretty much confirmed, but how about C++, or some other high level language (besides Lua)?
4. How do we make leaderheads? It doesn't seem "doable" by most of the questions I've seen from modders. Will there be a leaderhead SDK? Or a graphics designer for them?
5. Will new Firaxis-made leaderheads be available for inclusion into new mods on a d/l basis? I.e. can I d/l a Shaka leaderhead made like the ones included in Civ5?
6. Can we expect any sort of announcement containing any details of how the modding system actually works, prior to release?
1. Considering Dennis Shirk has been selling modding as more powerful than Civ4, to be true the intention must be to have the gamecore code released.
2. Considering Firaxians said that, I would believe it. Also, the Gamasutra job ad for community manager (Greg's job) specified having to know XML, Lua and C++.
3. See above.
4. NFI, though I imagine possible not.
5. You would assume that game content is usable in mods, right? Only conflict may be when the new content is paid DLC.
6. I doubt it.