No, not gay. He just had a genuine love and affection for Frodo because they were such close friends and because Frodo treated him as an equal. If the love that Sam had for Frodo was not there, the movie would have ended far sooner than it did. The only reason the Fellowship succeeded is because Sam was there and his love existed.

NO. Jesus I hate it when people say this, and they always do. Oscar Wilde, unlike John Ronald Reuld Tol-ki-en, was gay, if I recall correctly. So he'd have had more reason to portray his people (Dorian Gray etc etc etc) gay than otherwise.
That could be up to some debate. Wilde had relations with, and was married to, a woman at one point in his life. Sure, his downfall was because of homosexual activities, but that does necessariliy make him straight out gay. Bisexual, maybe. Socratic was the term he himself used to describe his sexual orientation, however. Really, he just had a love for beauty. At least, that is the idea I got from his works.