I think it would make a great essay since you'd have some kind of personal connection to it. Of course, make sure to not write it in a polarized way, since you don't know the opinion of the person reading it, and you wouldn't want to offend them. But if you can write it in a way that lays out the conflict and its impact in a neutral manner, I think you could do quite well.
Yes. Georgetown's policy will require you to send your SAT score, but if your ACT score is better, what will most likely happen is they'll just ignore the SAT score and look at your ACT score. The reason why they want you to send all your scores is because they want to see where your strengths are, so they'll look at your stronger score.