Does the candidate usually get notified when a request for a reference letter is made? I applied for a university position and gave the named three persons as a reference: A, B, and C. I am not very much in touch with A, B, C, but I already have permission to use their name as reference.

Would the university I applied to let me know that they sent a request to those persons – and whether they answered or not? For example, would they state that they contacted A and C and only A has sent us the reference letter?
Normally no, the university contacts any or all of a, b or c as they see fit.

They do not have to tell you who or when they contacted them.

They may contact a in the first round and b or c in the second - if you get that far...