Realignments traditionally help both parties in different states. It's not neccessrily an equal amount, but it does happen. For example, as California, New York, and New England trended Democrat immensely from 1956 to 1996, the South began realigning largely for the Republicans.
That's true, and we could very well begin to see some shifts in some states sometime within the next 10 years towards Republicans (maybe this cycle, or maybe 2020, and so on). I don't know which states, but I think at least Iowa and Pennsylvania seem to have some potential. I have mixed thoughts on WI/MI for various reasons.
We just need more data right now.
This will sound ridiculous, I fully admit that: we need a non-Obama, non-Trump election to predict trends 30 years or more into the future. Obama inspired a lot of minority turnout and support that previous Democrats hadn't, and he definitely appealed to some independents who would have maybe voted for Bush in 2000 and 2004. Also, Trump is (IMO) uniquely toxic to racial minorities.
