p.2 #1 · Using a system for a single particular lens?
Hasselblad 110/2 on an F body. I'm sure I would love it more if I did more portraits, but for the things I do I much prefer the 100/3.5 and the leaf shutter.
p.2 #2 · Using a system for a single particular lens?
Sure, I wanted my photo's to look like Sebastiao Salgado's ('Workers' era back in the '90s) so I bought Leica R gear. I didn't work, my photo's were crap. But I still have the lenses, and I still loving using them.
Nothing unusual about buying into a 'system' for a specific lens, or lenses. It's what everyone did back in the film days where you couldn't buy 1000's of third party lenses or adapt from other brands.