S80man welcome!! I like your tast in cars (being a volvo addict myself).
First off the european paint (like volvo) are thin and since it sounds like you want to protect your car from chips also, I would recommend looking into a car bra (colgan is the only one I can recommend). Many use the 3M clear bra which is a lot less maintanence (the car bras have to be used appropriately to prevent any scratches), but are expensive, are not removable and (more importantly to me) do not allow me to actually work on the actual car with waxing.
Now to your questions:
Yes, I definately would recommend a sealant. Sealants generally have better shine and the carnauba the dept. The sealants actually have uv protection, last much longer in rainy weather and more. I personally like the dept of using a carnauba, so I get a sealant like
klasse AIO as the base and you can top that with your choice of carnauba wax (make sure you wear shades!!

).
You do not have to really wait 60-90 days till the carnauba wax wears off. You can dawn wash it, or just apply AIO over it(it is a cleaner too) it. You then can top it with your wax (I prefer to put klasse SG as a second step before the carnauba wax. Better shine IMO).
Go with the car cover (if done right, there should be no problems with it).
Never park under any trees. Always clean any bird dropping quick.
Use a clay bar as part of your washing process (they are great for removing contaminants that washing could not).