No one can conjecture as to the cause of death; only the necropsy will show the cause.
Also, it would be very unwise to conjecture that the collection is safe if the necropsy confirms IBD.
At this point, I feel the best thing is to not let any snakes into or out of your home and get the necropsy done.
Also, I would be scrubbing like mad-- get every tub and water dish cleaned with a bleach solution, all utensils cleaned with a bleach solution, door knobs, walls, rack units, poles, scales, everything. Scrub everything down and start with a completely sterile environment.