Can you submit multiple appeals to multiple UC campuses? If so, will the other campuses be able to see the letter you submitted at a different campus (EX: Would UCSC be able to see my appeal letter to UCI?).
Yes, you can theoretically submit multiple appeals to multiple campuses but one of the reasons to appeal, is that specific campus is your top choice and should be noted in your appeal letter.
Each UC campus is independent of each other and will not see that you are appealing at different campuses but do not try to game the system and state all these campuses are your top choice??
If an applicant is appealing to a specific school, usually they state they will attend if their appeal is accepted. What do you plan to do if your appeal is accepted at multiple campuses? Definitely not ethical.