Depending on how the straps are installed on the pads, yes it can be a pain. On the other hand, quick-replace straps like the Smiths have are easy and you can do it yourself no problem. There is a guy locally who does gear repair who is quick, cheap and very good. He could probably do it for you easier than you could do it yourself, especially if they will have to be stitched in or threaded thru.
You will probably have to peal back the padding, but it shouldn't be too bad. Our cages get dented a lot, so most mask makers take the need for easy replacement into consideration. New screws and clips for most mask makes can be gotten via the Internet or the Hockey Stop if you need them. However be aware that cages are not interchangeable on goalie masks. Make sure you can get the right type of replacement cage before you agree to buy it, especially if it needs one of the old Jofa cages or something like that.
Definitely clean the gear. C/A, pants and throat protector can be done in the tub with mild soap. Everything else you can SaniSport. Just in case they had any fungus issues, you want to start clean. Masks can be cleaned with gentle soap and water (don't soak them - just sponge them off) inside and out. Be aware that if your mask is more than 2 years old, you may need to repad it for optimum safety.