Again, he's not wearing Trevor's coat! Trevor's is green, Alucard's is black.
LOL calm down.
And the coat doesn't look black to me in that first pic.
But maybe its the lighting?
And also, That coat doesn't strike me as something that can be found at your everday clothing market, and as you said, it may have been a coat given to Trevor by the order which even further raises the question of why the hell does Alucard have the same jacket as Trevor???
I would love it if your theory of Dracula getting another women knocked up came to fruition.
That way at least Alucard would be his own character as he SHOULD be.
But the coat and not to mention the "modified" combat cross says otherwise to me.
And also, I really don't have faith that MS will do Alucard justice by at least letting him be his own character.

I'm leaning more towards the Satan=Trevor's dead body=Alucard theory myself now lol.