Yes, because political parties in America always adjust to be 50/50 and it's unclear to me that the Republican Party has other places it can improve besides this demographic, but this will have the effect of changing the party rather than changing white Millennials' political opinions.
Yeah, pretty much this. I think it's likely that millennials will become more Republican, but it will be a matter of Republicans adapting their views to millennials rather than the other way around.
However, I would disagree that the parties
always adjust to be in parity. We've seen plenty of periods of long-term (~30 years) political dominance, and there's a totally plausible scenario where Republicans become the clearly weaker party in the country (at least outside of the Senate).