1. This is kind of funny when you think about it. I mean is Russia going to all of a sudden be very confused and think that the Americans gave Ukraine MIG-29s? No. Poland did. What's the point of the roundabout way of doing this? Maybe Poland is worried about intermediate range missiles targeting Polish airbases. But that seems like an escalation that Russia isn't interested in, unless they're in it for all the marbles.
2. This is further severing of ties between Russia and NATO-aligned countries. I expect other former Soviet Union states to follow and also acquire U.S. aircraft. They don't want to be reliant on Russian parts or technical know-how, and this further strengthens NATO around common aircraft and components. Expect American defense contractors (and some European ones as well) go get more business from countries such as Poland.
As I am thinking about this I think #2 is really what this is all about, but that Poland doesn't want to deal with transferring the aircraft to Ukraine and the Americans are glad to do it.