In MF you won't find much if anything faster than f/2,8 and the difference in DOF from f/2,8 to f/3,5 would I say is minor.
DOF in a MF neg seems, to me at least, to be shallow at those appertures.
Which focal lenght are you looking for in 35mm RF glass? Mind you that fast teles (75< ) are more difficult to focus than similar SLR lenses, the RF base on the Bessa may be just to short for that task unless you use e.g. a nikon 2X magnifier. If you want to stick with normal lenses maybe a Canon QL 17 GIII would fit the bill and a TLR with a f/2,8 lens could be a MF option.
An 80mm lens at f/3.5 has a 23mm aperture.
A 50mm lens at f/2, and 35mm at f/1.4 have a 25mm aperture.
That gives you basically identical depth of field among all three of them.
Just thought I'd throw that out there.
If you don't mind the square format, you can get a usable Rolleiflex 2.8 for quite a bit less. That will give you the continuous viewing of a RF and a quiet shutter, too. But TLR handling isn't for everyone.
Now if you went with a 4x5 rangefinder, even a 135mm f/4.7 gives reasonably shallow depth of field. Plus the wedding pictures would be fabulous.
Yes, a basic grown graphic with a 135mm or similar lens will deliver quite shallow depth of field. A comparable linhof or horseman VH-R would also be something to consider. All depends how much attention you want to draw to yourself. A crown graphic will probably be the talk of the room; not sure you want that.
For a really fast f/stop, the only choice is an expensive surplus aerial surveillance lens. Then you'll also need a shutter, and the lens itself might be larger than the camera.
If looking for a Leica at a bargain, I'd suggest the CL and then add a 50mm lense since it has the framing for it. These are great cameras and both quiet ans unobtrusive. When I got married, the photogrpapher used 1 with the 40 and 90mm lenses for the grab shots. More than half the time we did not even notice he was shooting. With the setups, he used a Bronica ETRS that was standard fare for many wedding photographers for many years. A few years later, I ended up buying the camera and lenses from him so they sit next to the wedding album when not in use and even if it were to break down would not be sold.