I've re-monokoted planes before, and had little trouble just peeling the old monokote off. If little shreds of it stick, take a piece of scrap monokote and iron it on over the shreds, then peel it back up, and it should bring the leftovers with it.
as for the mt dew scheme, unless you have a lot of stickers handy, I hope youre good at cutting out monokote just find coating in the right colors (take a dew can to the shop) and make a classy looking 2 tone scheme wit it, then plaster the plane with mountain dew logos and youll be set