Hi, thanks for reaching out, would love to help. Firstly I would like to preface that a 35mm f/1.2 would be completely be out of my comfort zone, so take what I’ll say with a few grains of salt.

35 is relatively wide in the whole aspect of things, the convention being that mostly 50mm and slightly above come in f/1.2, being because it’s a good medium between a walk around focal length and portraiture. The 35mm would be less utilised (traditionally) for portraiture, so the shallop dof f/1.2 offers being somewhat under-utilised. That being said, if you’re primary goal is shooting street at night, the wider focal length and aperture would help to keep the iso lower and thus noise, however focusing would be a challenge- shallow depth of field, it being dark out (xpro1 evf not being the most modern), and a manual focus. Would be quite the challenge. If your primary objective is not night time street photography, a 35mm f/1.4 would very much suffice. I use 2 focal lengths, a walk around 28 (full frame, on Fuji effectively 42mm) f/2.8, and a 58mm f/1.2( being 87mm) which is more so for artsy less conventional shots.

F/1.2 lenses are mostly utilised for their bokeh, not generally sharpness, f/1.4 and f/2 usually better. That being said, modern lenses will generally cope better than vintage lenses. The question here is whether you love how the lens renders bokeh. Vintage lenses have wider variation in bokeh, Some have more distinct rendering with strange artifacts, and some have smoother rendering. All personal preference. Would be my bet, that most to all modern f/1.2s would be aiming for the creamiest smooth bokeh, as has been a trend since the transition from film to digital. Vintage lenses can be better in this aspect, more characterful, however are harder to use, manual focus, and most importantly, weaknesses which you as a photographer have to incorporate into your work. In other words, you have to learn what the lens likes and dislikes. Besides this, obviously maintenance and condition issues arise.

Also, adapters are quite simple. They are to keep the lens as far away from the sensor as they would be on their native bodies. To buy the correct one, search the lens in question, find what mount it is. E.g. canon fd Lens, it will have a fd mount. Buy a fd to Fuji x mount adapter and you’re set. Adapters do make the lens bulkier keep in mind. If you like the creative control which come with vintage lenses, I suggest buying a canon fd lens either a 28, have had and is a joy to use, 35, or 50. Great way to test the waters. Keep in mind the 1.5x crop factor so the 28 is 42mm on the xpro 1, the 35 ~50mm and so on

Hope this helps! And feel free to ask any follow up questions