I see so you use the slip down final as an educational tool if I understand correctly. I also do low approaches and let them slip the airplane down the runway to get the hang of it. That works well and its quit fun too... you do need a longer runway though my home field is quite short for that.
In a crosswind landing I teach to keep the airplane crabbed on final until the flare and then "kick the crab out" and go into a slip. Being crabbed on final does NOT mean you don't use aileron, you should be correcting for everything with coordinated use of aileron and rudder. The only time...