-Is it acceptable to utilize the hydraulic levelers to raise the coach to change/pull the tires for clearance?
Yes but you should treat the jacks no different than any other jack that could fail without warning. Get jack stands if you plan on doing your own tire work. Northern Tools sells 12 ton jack stands for around $80.
-How do I verify that the TSB/Recall work was already performed on my 8.1l workhorse chassis for the front brakes?
The dealer should be able to check recall info using the Workhorse network and the coach's VIN. You can also call them with the VIN to check.
-What would be the best, but readily available wash/wax for the outside?
Lots of opinions on this one. I hand wash once a year with dish soap, heavy stains get a scrub with Barkeepers Friend and then I use with Red Max Pro (RPM) for a shine. Coach is good for the year uncovered in my drive way.