This. You'll have to let up just a bit Matthew.
One person can't make a decision about every design detail, that's why you hired some professional designers. That was a smart move.
Now you have to respect their decisions. I can assume that as chief editor, you're already exerting full editorial control of the content. A lot of the details (whether editorial or design) are just minutia and you must let go. Everyone will still love the magazine even if it isn't perfect (nothing is perfect!). But if you don't let it ship then we're guaranteed to hate it!
Forget about the models and everything else. Think about your team. The magazine needs nothing new right now. It needs to ship. The longer this goes, the more morale fades in the team. Eventually, the money will run out.
Write the letter from the editor, issue #1. Then listen to your team and let them finish.
Real artists ship.