To me, Hezbollah initiating hostilities against Israel even in their weakened state shows that although they all operate with some degree of autonomy, Iran ultimately does in the end call the final shots with each of its proxies. Now of course there's no conspiracy about why Hezbollah sat out the last round of hostilities, Israel gave them a pretty heavy beating and they needed a breather to regroup. But I think also because the 12 day war was not quite existential for Iran yet, there wasn't a need for its proxies to step in.
Now with the war indeed being existential, Hezbollah is already forced to fight no matter what. Like Iran too, they are adjusting their strategies accordingly. Their missile launches are more piecemeal rather than seeking to inflict any damage on Israel, because unlike Iran which is over a thousand miles away, Lebanon being Israel's neighbor means its much easier for the IDF to detect launches and eliminate them accordingly. Rather the missile launches are meant to goad Israel to commit to a ground invasion. In this regard, Hezbollah has a much better chance of fighting the Israelis on equal terms, not least because they are likely much better organized this time around and Israel doesn't have the element of surprise. Combine that with the arrogance both Israel and the US are exhibiting and Israeli ground troops may find themselves sleep walking into a meat grinder against fanatics that are done with political posturing.
But the ultimat point of this analysis is to get to the one Iranian proxy that still hasn't committed and that's the Houthis. My take is that contrary to what some are thinking, they are absolutely not sitting this out, it wouldn't make sense. They are far enough away from Israel to have escaped their decapitation strikes, the fighting in Yemen has been relatively low intensity in recent years so they are still at relatively good strength, and they were amongst the first to come to Gaza's aid after October 7th. Iran has been very methodical in its rocket launches and its coordination of its proxies this time around, so I believe the Houthis are lying in wait for certain pieces to fall in place until its their turn to step up to the plate. Perhaps something to do with Saudi Arabia? We shall see.