Not sure on disassembly of tub faucet

Hi everyone. I'm trying to help out some older relatives with leaks and other issues in the home. I fixed some cartridge faucets but in another bathroom pretty much all the fixtures of a tub are leaking (apparently it hasn't been used due to the leaks for some time). It also has different types of faucet handles than the ones I was able to easily fix. I'm going to attach a photo of the above and below. It seems like the very top (with the stem) doesn't want to turn independently of the rest of the fixture. I'm not sure if that means I have to take the hardware under it apart to get to washers, etc.

As you could guess, I'm new at all this but hoping to get a grasp on it so we don't have to try and call for simple repairs. Thanks!

thread the chrome body back on...that will give the faucet more stability...and use a socket on the exposed stem....

Warning! Use of the socket I agree with, but you also have to back up the valve body below or you will mess up the supply connections.
Two people will likely be required.

Sounds good. I wanted to make sure that I was trying to disconnect the correct part, if that makes sense. I'll see if I can get someone able to bend enough to stabalize the bottom!

Thanks, with a second person and when I was willing to really yank it, I got the two handle fixtures off and replaced the innards. But the problems don't end there.

The spout is leaking from the diverter and I can't seem to get the spout off. I'm attaching a photo of the hardware under the spout (and the above one shows a different angle. I tried backing off the cover(?) with marked with the blue arrow and still couldn't twist the spout off... at least without wrenching it hard, which I'm again worried about doing unless I'm sure it's what I'm supposed to to do!

Also... another leak is marked with the red arrow. I would imagine there's supposed to be a cap on that part?