It worked!
I don't know if I'm just lucky or if this is a temp work around but I am back home on Excal for this first time since patch. I was able to jump from Famfrit to Excal using the Aetheryte in Grid using the Visit Another World Server option.
Edit: I was able to check retainers, go in housing, teleport normally, everything seemed perfect working order. For science, I logged back out to see if it fixed my character.
It did not.
I got same 90002 error logging into Excalibur and now am trying to walk through the hopeful workaround again but already hit a snag... Leviathan did not work either. I'm trying to roll for Famfrit again since that is the one that worked the first time.
Edit2: I got another Famfrit roll FINALLY but... It did not work. ):
It must have been a lucky login. I'll try a few other worlds for fun but I'm thinking its random now lol. Still a lot of hope that maint will fix this!