1. While I think jersey retirement usually sparks its own thread (or threads) throughout the season, I will give a partial answer. If Kyle is his normal silent but deadly self, he will not win NPOY. NPOY would be Sullinger (IMO).
2. If Kyrie comes back, I think he would start, but we would continue to run our offense as we are now (a bit slower than earlier in the year). I thought I remembered Coach K saying this in an interview, but I can't seem to find it now. Maybe some else remembers and can find it.
Kyrie is a better PG than Seth, so Kyrie would start. Nolan will continue to attack from the "2." Kyrie would be able to break down defenses when we need a bucket. It sure would be a fun way to finish out the season.