I think all bets are off on wax/sealant performance if you're applying them over a glaze. There's no way to know what could or would happen. With that stuff on there now I think the best approach is to use a coating/sealant prep polish to ensure the surface is ready to accept a sealant. You could use finishing polish, but then you likely need a panel wipe to remove polishing oils.
Dawn may or may not be causing a problem. I would use a car wash soap.
You don't need to remove polishing oils to apply a wax but agree about the glaze