There is a substitute for rocketmod in Unturned II, it's called create your own plugins. Also, the closed beta is just a vehicle demo, nothing special relating to how finished the game is. There is without a doubt going to be developers working on new plugins for II, servers that depend on rocketmod are just going to have to wait until devs start releasing things in Unturned II.
If there are substitutes that the players and developers make, you, as you have stated, are you going to have to wait until they are released before Pandahut comes back up. If you can migrate to not using mods and plugins and working that out, you won't have to wait when Unturned II finally comes up. You can figure some of it out now, as you still don't know EXACTLY how servers are all gonna work in Unturned II, then figure out the rest later as plugins start being added. The commands and lack of commands can still be abused, either way it goes, but trying to keep Pandahut as active as possible is important. Of course, Unturned II may not be super close, but it's coming nonetheless. Might as well start now.