My take on your rifle is to restore that which is deficient about it. You can reconvert it unless the percussion conversion has great merit, (there are some that have very artistic conversions to caplock and should not be messed about, (they seem to be in the minority of such conversions however). I have a Peter Angstat rifle that was converted in Bedford County, PA. The rifle is a very baroque looking piece and as it happens; the conversion fits the gun perfectly. Reconvert? Never!
Any missing wood is fair game for restoration; my standard is how it affects the eye. If the stock (or whatever) flows smoothly, why invade it with replaced wood. If it impacts the eye and is a distraction, (e.g., broken off forestock, in most cases), then restore it. I have a Santa Fe Trail rifle made in Somerset, PA though, that has had the wood along the forearm shelled off. It was done during use and the breaks are even rounded over on the edges. Old timey cleaning, rubbing and use rounded them.
It is still that way and will remain so. It looks just fine and given the history, it will stay that way, while I have it.
Finding the star and fixing it is a must! A little story here. A collector some years ago bought a fine original rifle built by one of the best So. PA makers through a broker. Fine, beautiful gun with the cheek rest inlay missing. Big problem! Buyer demanded the sellers' name and contacted them; he told them that he now had the rifle and made an astounding offer for the original piece of silver if they could find it. Guess what? They did, and now the inlay and rifle are back together again. So, point here is that small things can be more important than we think.
By all means fix the patch box lid and secure it again. You don't have troubles until you lose, or get a rifle that has the door missing. Ask JTR how he feels about PB doors.
Don't touch the patina, the carving or the brown on the barrel, lock, or anything else. On the other hand, if the ramrod is missing, have a replacement made.
You have been given some good advice here (some of it is better than the rest) and given the names of some good restorers. Each of us has our favorites, no doubt, but there are many true artisans out there who can recreate what is lacking (impressive, though new) and then knock it back to look like the rest of the rifle so you won't be able to see what, or where work was done.
Looking forward to the photos.
Regards-Dick