That's great! Of all the stuff you described, separation anxiety can be the hardest to fix, so I'm really glad to hear you two are making progress with that.
It sounds like he has free run of your place while you are gone? Have you considered getting him an xpen or crate? That would help with his destruction, given that he can't destroy stuff he can't get to
, and it's also a huge help with potty training.
Thanks for letting us know how you're doing.