Congratulations and welcome to the site.
1) For a while Lippert recommended lubricating the slide (there even is a
about it). Then lately we've heard not to lubricate it. Take that as you will.
2) Yes it is a good idea to only run the slide all the way until it stops and hold the switch down an extra few seconds (also do this when retracting) this allows the motors to stay timed. Having said that, our drop down bunk also uses the Schwintek mechanism and, when camping, we don't raise it all the way during the day but still re-sync at the bottom and have not had any issues with it.
3) Yup that is the best answer, get some leveling blocks and put them under the wheels. If you really want you can have a truck shop raise the suspension slightly on the slide side.