I think i read that you wanted to buy a tank. I'd advise against that. I learned to dive here in the Philippines, a third world country in some minds. I retired here a year ago. I was born, raised and spent my entire career in the US. My advice is based on where I live and where I came from.
I alway rent tanks filled. I have about 80 dives under my belt at two dive operations here and, here in the Philippines, I haven't even had a hint of a problem. One motivation for buying a tank might be that "at least i know i have a good tank." There really are no bad tanks; bad air is a much more common occurence...and even that isn't common from reputable sources. Rental tanks full of good air is the way to go here. No reason to schlep a 30 pound lump of metal around. FWIW, the dive shop i use the most has even offered to store my weight belt and weights in the shop...taking 8 pounds off the dive bag i have to drag back and forth.
All the other stuff you mentioned makes sense to own and asking around...including here is a good way to get decent advice. I think you can squeak by for under a 'thou' for the dive comp, reg/octo and bcd but it would be tight. You don't need a state-of-the art comp and you don't need the latest, greatest reg/octo. You wear your bcd, though, and its fit and ease of operation will make the difference between easy, competent dives and dives where you are constantly 'fiddling' because your bcd doesn't fit/feel right.