Thanks Troporobo for the detailed reply.
I'll try and answer your questions as you asked them:
1: As to how much gear I can handle, i would say a fair amount, I was scootering, shooting video (with an old style big assed housing) with stages in the past. Obviously, with any new gear additions, it would be a take it slow approach, initially just the rebreather & camera, then slowly increase task loading till I am comfortable to handle what I have with me.A smaller package is better so the mirror-less seems like a good choice as it would be easier to bring along/clip off when caves & wrecks.
2: As you mentioned my interest is in WA wrecks & caves with divers usually in the foreground.I really do not envision myself doing small criters in macro. Mostly low ambient light or none at all though some with be caverns with natural lighting in the background. quite a few areas I dive in have a lot of particualte in the water so the closer I can get to my subject the better. Looking at the compact mirror-less cameras, from what I understand (I could be wrong) the focal length is effectively double what a DSLR is so a 8mm fisheye is effectively a 16mm......would this effect my shots too much?
3: Budget.....well that's the big question....like everyone,I want the best for nothing but understand that is impossible. I see myself getting real good strobes with optical connections, as from what I was told...good strobes can last you a very long time. I do not see myself changing housing/camera after I purchase it...as I am not a fan of buying gear just to upgrade it a year or 2 latter. ( my last scooter was purchased 9 years ago, and only recently changed as I am getting too old to lug around 90-120 lb scooter to the shore ). Glass optics/dome is important as being in a wreck/cave environment lends itself to the possibility of some accidental oppsie's.I can also see myself just getting a housing/camera....playing with that for a while and then getting strobes at a latter date (new or used), using white balance adjustment to get the colours correct in shallowish water. Though I would love to be ready with the whole kit when I travel to Truk Lagoon next year.
Again, thanks for the time you took to reply.