Why is there a -’n there?
Thanks so much, ibisc! I was really confused about this.
Why isn't Aelod o'r tîm dych chi? valid here?
It is valid and it is one of the accepted alternative answers.
Why is it "aelod o'r tîm" and not "aelod y tîm"? Does the former mean "one of many" and the latter mean "the only one of"?
aelod y tîm would be "the member of the team" or "the team's member", due to how these noun–noun combinations work.