Yes you can get distortions, especially at splices where the film may not sit perfectly flat. No mechanical process is perfect, so you do get some distortion sometimes that is highly visible, with warping, out of focus areas etc. and very slight distortion that would only be noticeable if you compared them directly, but you would’t notice otherwise. Contact prints can also get newtons-rings type problems, which again, might not be highly visible, but can distort the image slightly.
Averaging a bunch of release prints gets you a little closer to the original, you negate some of the effect of the individual print grain, and if you use the correct stacking methods, might pick up some extra detail/resolution that is in one print versus another, but it is tricky, you might just end up substituting noise from one print to another in some areas.
You are never going to even get close to the negative however. The release print is timed differently, often throwing away 4 stops or more of exposure latitude, often intentionally.
And there is loss going from an IP to a release print that is lost forever it won’t be there in any of the prints, (e.g. the dynamic range etc) so it can’t be recovered, but yes if you had an infinite number of release prints, you could get close to the IP, assuming you could scan at a crazy high resolution so that the warping of every frame that you would need to do to assure perfect alignment between each print before stacking didn’t just smear out the detail anyway.
So what you get is something that gets closer to the timed interpositive, rather than getting something that is close to the original negative.
In practice, unless you are averaging a lot of prints (like a dozen) the effect isn’t always better than using smart algorithms to reduce the noise in a single print. The prints need to be perfectly aligned for it to work properly, otherwise slight misalignment is reducing detail, so the net affect can be worse. It is however helpful for recovering data where you have a lot of damage on one frame, and no damage on the same frame on other prints.
Back to resolution, it is kind of difficult to put a set number on the resolution of film, measuring a pixel grid is different to the randomness of grain and dye blobs, and the resolution will vary with different exposures, colours and contrast. Even the grain representation looks radically different at different resolutions, we just finished testing grain reproduction at different resolution levels. I’ll post some of our results later if I can get clearance to do so.