No, there are no click stops. Only a hard stop at full open and full close. 

no it will not the eos-r has a different mount 

yes, i had no problems with infinity focus with this adapter. the only FD mount lens i use anymore with my sony is a vivitar 20mm, and i pretty much only shoot infinity focus with it. 

The adapter clicks on the lens. It has a small dark gray colored lever (not the white plastic tab to change aperture), level to the outer edge of the bottom ring accessible when removed from the camera, grab the whole adapter with your left hand and push the lever in with your thumb, and while pushing, rotate the lens with your right hand to remove it. You need to push in that lever to unlock the lens. 

An adapter does NOT change the focal length regardless of what is mentioned in the 1st answer. The adapter *can* be used on a camera with a smaller sensor which would change the filed of view of a particular focal length.