> ... but so have many other gay men [used feminine pronouns]

I have never met a gay guy who preferred to be called 'she'.

> Wouldn't using a masculine name and wearing masculine clothing be grounds to consider her in fact a him, a transgender man?

This is all moot. The only one who is to decide is the person themselves. Trying to work out the correct backpatched term is a waste of time as it's trying to read a dead person's mind.