-- Wrist straps: Dunno.
-- DAG will work on the RF mechanism and there are some other independents (check old threads) who will work on the shutter etc. For electronics, Epson might be your only option.
-- Latest ACR works fine, and so does Lightroom (although it's more a complete raw-file management utility, not just a converter, so might be more than you need if you just want to convert your raws to another format.) The bundled Epson PhotoRaw converter is very good also, especially for b&w conversions, and the price is right. If you bought your camera used and didn't get it, you can download it via a link on Rich Cutler's excellent R-D 1 info site (click here.)
Iridient Digital's RawDeveloper is a good bet if you want a LOT of numerical control over your conversions. There are others too.
-- Other things to consider: I'd say one or more spare batteries should be at the top of your list. The battery doesn't last for as many shots as those in many modern DSLRs, so it's nice to have extras. Epson batteries do seem to give more shots per charge than independents, so they're worth the extra cost IMO. You have to watch the Epson online store to see when they're in stock; they come and go. Beyond that, once you've shot with your 35/1.2 (excellent choice!) you might want to start thinking about another lens or two, but that's really about all you really need.
One of the beauties of the R-D 1 is its spartan simplicity -- you don't really need a huge "kit" to get the most out of it.