1. In my humble opinion, 'who' functions as a subject.
2. Yes, I believe they are both correct.
3. The past participle of 'go' is 'gone'. 'been' is the past participle of 'be'.
I know what you mean, though. 'been' as in 'have been to' means like...'go'.
I'm not a native speaker of English.
Please wait for native speakers to respond to your query.