Al,
About 5 or 6 years ago, I was hit by a hail storm at 2 am when I was in Dumas. Now back to your problem. Your coach came with Fantastic Fans, and the vent covers on them have a lifetime warranty against breakage. So all you need to do is call Fantastic Fan and tell them that your vent covers are broken and they will send you new ones free of charge. However, since they were purchased by Atwood, you are now required to pay the shipping charges for the new covers.
The sealer is not too hard to remove, just use a sharp gasket scraper and reseal the screws on the new vent covers with a good flow grade sealer. The shower skylight will be a lot more work to clean the sealer, but it is doable, so take you time. BCS (Beaver Coach Sales) should have a new skylight to fit your shower in stock.
Gerald