I have a 500 and a 501, but I unfortunately can't answer your question about screens as the 500 is 2500 miles away! Sorry!
As for straps. If you can get the clips, you can attach pretty well any strap you want to it. I bought the leather palm strap for a grip and took the fittings off it (they are the same as used on the camera body).
Handheld, a 501 kit can be wonderful, and that is mostly how I use mine. Of course they're great on a tripod as well. My 80mm is my favourite/most used lens. The distagon 50mm f4 is also a fantastic lens, in my opinion.
To answer your question about a strap, I have a perfect solution (in my opinion). I use David Grubbs' Wapiti Straps on my DSLRs and I wanted to try to rig one up to my 500CM, so I cannibalized the original clips of a very weathered and worn out Hasselblad strap and threaded the Wapiti Strap onto the clips. Works perfectly! Supports the weight of a V-series camera comfortably and is able to be ordered in any length as well. It's like $33 from David's website.