If I am right, the whole rear triangle of the bike moves with the suspension?
In that case standard mudgards and a three point rack will fit.
By a three point rack, I mean one like
this where the two legs fit on to one of the pair of holes by rear axle (3rd image), and the other fits onto the hole in the 2nd image.
All you need to do is "offer it up to the bike" before you purchase to ensure it won't affect the rear suspension travel at its limit
Won't carry as much as a four point rack, but will carry more and be safer than a seatpost mount as these can swing into the wheel