Gosh, you ask some tough questions!
I love to see men in and out of just about everything! Whether it be on the beach, at the pool (you don't see many thongs on men) so 'good on ya' to any man who wears a thong - you will get fingers pointed at you and giggles from most of the folks, but I love the confidence in a man who wears something out of the 'norm'. European style / speedo type swimwear is my favourite (I hate to see men in baggy shorts or board shorts at the beach or pool). Nude is great, too!!
Slacks at dinner is 'important' to me. Dress to impress.
At the disco - costumes, something fun, briefs, colour themed outfits - whatever you feel comfortable with.
Rest assured that this is one woman who actually looks at and notices the men and what they are wearing. For us, it's not ALL about the women. Couples are a package deal.
Have a fun trip!!