So, what if Kamala becomes president? Ripple will definitely expect something back for their support.
I don't think there's anything she can do for them, not legally at least. The case is too in the open for her to do anything illegal. She is not the one in charge of the case; it's the SEC, and she can't influence that.
And what if politicians take donations in altcoins, like how Trump also received some? Does that mean their decisions on regulations could end up favoring altcoins over Bitcoin?
There is no decision on regulations that would favour altcoins over bitcoin. They can only make regulations that might favour that particular coin, which would favour bitcoin. There is no way you can be against Bitcoin and be for other crypto projects. It just shows you're a greedy fraud who just wants to make money, and politicians wouldn't want to be seen that way, even if they are that.
All they can do is make favourable laws for crypto which also favours bitcoin.