Hello, if I am correct, then the BM Cinema Pocket 4K has an MFT mount .... then it would not fit. This has an EF mount .... but there may be an MFT-EF adapter.
Check what kind of mount your BM has. If MFT, then it won't fit without an adapter
Nikon has different autofocus systems and some lenses require a specific motor, which the D5600, for example, does not have. I am not sure if this lens needs this motor.
If there were any, people would certainly have read about it. It's been on the market for two years. But I have only used this great lens on the A9. You simply can't find a better 50 for the money. I've been using it since the E-mount version came out (summer 2018).
No, there are no problems. The AF motor works very fast, not quite at Canon L level, but in practice I never had any problems. It is very precise and never pumps, which is a big plus when filming!
Yes, it fits, it's just no longer a 50mm but an 80mm (in terms of the angle of view) because it's a full-frame lens. But it works and can be used well. The weight of the lens is a little high for the 60D (front-heavy).