There are rentals at the lower and upper cable car stations. Basically, the equipment isn't too new, but it's in good condition. Part of it has been replaced by a newer one. If you're looking for new and better equipment for piste riding or freeriding, you'd better take care of it in Mestia.
There is no information about the availability of an instructor school at the resort. Professional instructors will have to be searched hard. A good strategy would be to find an instructor in advance, or come to the resort with your own instructor.