A few points:
I would expect that most Minolta Lens → EOS Body Adapters, would have an optic to maintain Infinity Focus – without an optical element the rear of the lens needs to be shaved to get to infinity focus.
The aperture of the lens will probably stop down via a spring loaded aperture lug, which extends from the rear of the lens – when the lug is held against the spring tension it will stop down.
If it is the one of the Mounting Bayonets which is broken on the C/Y Lens and it is loose on the Camera, then it will likely be loose on the adapter: BUT the lens will be connected to the adapter, so you could secure it, semi-permanently, with GAFF tape LOC-TITE or something similar. BUT – if the lens has physical damage then that could be as a result of an impact. As I mentioned earlier, the C/Y lens would need to be in good condition for me to consider using an adapter for it.
WW