For connectors my go-to is Deutsch (TE/AMP)
DT/DTM/DTP series, depending on ampacity required, some go up to 12-pin.
Andersons with weatherproof booties usually good enough.
For caulk, Sikaflex or 3M, the marine stuff. Be careful when they say a sealant has strong adhesive properties, like 5200 they ain't kidding, only for bits you plan on never undoing.
For potting and conformal coating, will let others post, I'm still a noob there.
