Re: End of the regular season: top 16 team view.
Big assumption to make about Georgia & Tennessee as locks to host. Remember that they still have to play in the SEC tournament and a loss in the quarters might be enough to do either of them in. They are the 3 and 4 seeds in the SEC tournament, so they will have tough 4-5 and 3-6 matches and it is conceivable that a couple of teams like Ole Miss or even Vanderbilt could make strong runs through the tournament and take away top-16 spots.
Also you're probably right about South Florida being out of hosting but it is by no means a lock. At this point it is really too far out to rule anyone out, assuming a team plays in a strong conference, has a conference tournament, and still has a chance for some good wins. The loss against ND isn't going to hurt USF that much and maybe a win against DePaul in the Big East tournament combined with some bad losses by teams ahead of them in their respective tournaments gets them in. Also, though it is unlikely, a win against ND in the conference tournament would likely get them into the top 16...which as we have seen in the last few years doesn't guarantee that you're going to host anyway!
Probably right about most of your predictions, though I wouldn't call most of them "locks" just yet. I think a "lock" is a team that, even were they to lose the rest of their matches, would still be where you project them to be. With so much tennis left to play, I just don't think that you can call anyone a lock for anything at this point. Even if a team is in a conference with no conference tournament, they are still at the mercy of what the teams above them and below them do. A team ranked 42 today and static this week could have the bad luck of having the 43-49 teams do well in their tournaments and could find themselves out of the NCAA tournament.