1. Not sure about Mitakon, but any adapted lens reads F1 and as all MF lenses have marked Aperture ring you always know your settings.
2. For decades, decades and decades MF lenses were the only option for all types of photography. I shoot film a lot, so I shoot MF and have no problem with street photo.
3. The only condition you may have issues with nailing focus on moving subjects is darkness, when the SS falls lower then 1/60 or 1/250 depends on moving speed.
That technique called Zone focusing (a lot of explanations and youtube videos). You need DOF calculator ( https://www.photopills.com/calculators/dof ) and to remember how far is 5 and 10 meters away is.
Let's say you are shootig during the day and going to capture some scene at least 10 meters away (everything closer then 5 meters with 35mm lense I would consider "street portraiture"). Usually street photography assumes planty of DOF so it's F8 and more. Thus our calculator said that everything from 4.34m to infinity we would have in focus.
So you select 10m and F8 on your lens and don't bother about AF any longer, just correctly estimate 10m distance - plus/minus 3m. Do some practice. )
Another scenario is the low light conditions when you need to open your lens. But even with F2.8 you will have almost 12m of DOF.