All the characters act gay sometimes. The Writers think its funny and it is but it confuses people. None of the characters are gay, the writers just like to have fun.
Umm,this is a debateable question if there was one...look,how I predict it,the way things are going for Brian relationship issues wise,he might turn to Stewie.But hey,as if the first Family Guy movie indicates,the relationship might be a rocky one and might not last,so who knows?