I think you’re right, they do share SOME info, but not all. Like they don’t share your BOC and the reasons of the notice of decision. However, they do share your medical and background check.Hopefully you will. I don't know if it has anything to do with making your claim in canada. but there i did biometrics again and also a medical. my background did take a while which is why my hearing was postpone for like 2 years. so i don't know if immigration and IRB share SOME information. which may be why i was never asked for any of those.