To answer my own question, there are eight if you include lycanthropy which would cure the other 7 and thus should not be included. Woulda thought more than that though this may still be a decent basis to create a trial around it. The use of the Bloodspring in Redwater Den should be disallowed.
Maybe the candidate should contract the applicable 7 diseases and then have to assassinate all of the temple healers in the varoius cities and towns. I think most are either non-essential or can at least become that way after completing a radiant quest involving that person, Danica Pure-Spring and the Gildergreen quest for example, so where possible to do so, the candidate should complete quests that will allow the giver to become non-essential and then kill them afterwards. We wouldn't want healers to get in the way of pestilence and plague now would we?
Perfect, except I think there should be more, So I'll add input.
• Restoration is the sinners way. No restoration magic shall be used.
• To add more, I'll kill every priest of every city or town in Skyrim. That includes all vigilants, healers or priests.(Edit : Alchemists too.)
• We need to do something with Spellbreaker as well, considering its Peryite's gift.
I still feel I need more, it's already a more than manageable task.