Crypto detection is infuriating because you can't know if it's actually gone. Six months is solid though. Did you change anything, or has it been the same routine the whole time?
does he know anything about where she came from? sometimes they're already gravid if they've been around males before, so the timing might not mean much
I'd wait before changing it up - new geckos stress pretty easily from just moving, and it'll adjust faster if you give it time in the current enclosure before making changes.
my gecko did the same thing for ages. ended up being less about the supplement and more about which feeder insects i dusted them onto — made way more difference than i expected
The not eating and hiding for the first few days is normal stress from moving. On the nocturnal thing though — if he's nocturnal, he's probably always going to be more active at night, not something that changes. Once you figure out what species you've got, that'll help you dial in the heating...