The squeal is normal, unfortunately. It's surface rust on the drum. As far as wheel bearings, check on this forum as a lot of folks swap over to oil bath hubs. Cost isn't that much difference than a bearing pack other than a new hub cover.
I know that the manufacturers all suggest annual bearing pack and inspections and that's fine, but in reality it isn't done by that many folks and I don't see a lot of coaches off on the sides with bad bearings. You should do them now to satisfy yourself as the factory isn't the most generous with grease at times. After that it's your call. Oil bath eliminates the need to do anything with the bearings unless there is a leak or other issue.
Trucking companies don't inspect many bearings as a course of normal maintenance - I hear about that comment in sure. We have the luxury of worrying about all this stuff and probably more free time on these forums that is the RDA.
Do something with them now, and you will have a starting point from here.
1998 Signature 42' M11 450hp - -pulling 25" enclosed trailer with SCU sandcar inside
Lovely Wife, 2 kids, 3 dogs, 2 cats
Diesel Mechanic to the stars