There's so many possibilities that there's not much benefit in speculating until Google actually shows their hand. It could get even more confusing than it is now.
Will they release VP6 and 7? The former is supported in Adobe Flash and the latter is used in Skype. VP8 isn't used anywhere yet, therefore backwards compatibility is moot, so will Google rewrite the spec to suit their own particular needs and plans? Have they had time to do that yet, or are they just going to announce what they're planning to do over the next few years?
Despite many geeks focussing on the simplistic comparisons of complex and tricky benchmarks, the business relationships are going to make or break any new codec just like they have done for MPEG codecs. Are the patent worries real or is that just a convenient smokescreen for companies that have decided to throw their lot in with MPEG because there isn't corporate-friendly competitor? I guess we'll find out.
My personal guess is that freeing VP8 as-is would only make sense if they convince Adobe to roll out support in Flash. Otherwise they'd be best playing the long game and getting a royalty-free standard based on it passed by ISO or whoever.
There's some good analysis of what freeing VP8 would involve here:
Regarding your question on Vorbis, I believe it's the only real candidate for such a role, it is technically very good and I've seen people who are incredibly paranoid about video patents have no issue with it. I'm surprised more fuss wasn't made about this at the time it was removed from the spec. It appears that on the web audio only matters if accompanied by video.