Snake mites have about a 30 day life cycle so watch for a re-hatch in that time frame. You may find that you need a different product to totally wipe them out. Did you notify the breeder that the snake he/she sold you came with a not-so-complimentary case of mites?
As far as feeding, it's best to let the snake settle in for about a week with minimal fuss or handling before offering it's first feeding. It's also usually easier to offer a new snake the type of food using the method of feeding that the snake knows already. After a number of successful feedings you can then start the transition over to other prey items or feeding methods.
Handling, to my mind, comes last after you get the snake settled and feeding properly (and get these mites dealt with). You've got literally years to handle this snake but only a relatively short time to smoothly settle it in so my advice is always to focus on that and keep the recreational handling to a minimum at first.