Using Richter's model for TNG-R would be no different than using Koerner's model for TatV (other than Richter's is better :P ). They're both digital artists who happen to be Trek fans and got to work on the show.
At this point we don't know anything other than what we've been told (the CG model has not been used yet). Anything other than that is pure speculation.
Yes it would. Gabe was working at Eden FX at the time who had the gig to work on Enterprise. To my knowledge, while Tobias is a pro who's been doing it for many years, he has no official relationship with TNG-R. Unless of course its just kept quiet.
And Richter works for The Light Works, which is working on other Star Trek related projects for CBS. Would it really be unreasonable it think they hired his company to work on this too?
My whole point, was regardless if he is or isn't working on it, there will not be any official announcement, just as there is no official announcement that The Light Works is affiliated with TNG-HD.
And the difference between Gabe and Tobias, was that Gabe was working at the actual studio who had the job to do FX. To my knowledge Tobias does not work at CBS in LA in a role animating shots. Pretty big difference.