Allright, I think I got all that. First, I don't like the rule but oh well, that is not your issue.
Due to the fact that there was some confusion and uncertainty with this transaction I would err on the side of allowing him to have Gonzo on his starting roster. If at 11:30 when the inactives are declared the absolute decision should have been made and Hixon removed from his squad once Gonzo was not listed.
I think there were mistakes on both sides. Based on this quote
I put on the message board that if Gozalez plays, Hixon would be removed from his team
it could be either I am simply removing Hixon or I am removing Hixon and putting Gonzo back as a starter. Personally, I would have left it alone and not adjusted his roster at all until after the games were complete.