Israel will definitely retaliate (for the strikes that are retaliating against its strikes, it just goes round and round.) The US is moving naval assets into the region so they’re apparently taking the threat seriously. It was a combination of the US, UK, France, Germany, and ~50 other nations that voted to declare Iran in violation of the nuclear non-proliferation treaty so they likely have a vested interest as well, but Europe isn’t nearly as gung-ho about this sort of thing as the US is so they’re likely to let us take the lead if it goes that far. Iran’s neighbors have been trying to normalize relations with Israel for a while now but Israel doesn’t have puppet strings on them like we have on Israel so they likely won’t get involved either way. This is probably going to stay an Israel-Iran(-US) thing for a bit, but again it depends on how serious Iran wants to take this. I expect their losses in enrichment facilities were something baked into the cost of the program so they’re probably not too stuffed over that, but they’ve lost at least two high-ranking military commanders that I’ve heard of so far and that thing does tend to get them cranky in the pants. I suppose the Houthis in Yemen are kind of a wild-card considering they’re supported at least to some extent by Iran and have no compunction against bloodying Israel’s nose (see all the ships they’ve attacked in the Red Sea recently), but also they’re not likely to be able to accomplish much more than a token effort.

Honestly it’s all speculation at this point. And I’m by no means an expert on geopolitics nor do I have the latest information on the region, so that’s particularly wild-assed and largely-uninformed speculation to boot, so I’m not going to try to lay odds on it. My gut says it will probably just be an exchange of blows and settle down like these things tend to do, but the rhetoric is in high gear so there’s definitely the potential for more trouble coming down the pike.