Recently I grabbed Sarthis Idren, Lu'ah al Skaven (I think that's her name), and two Master Vampires. I dumped them all in Breezehome and they've all disappeared! How do you keep thralls safe? D:

Not sure what you mean by "dumped them all in Breezehome"

I thought the maximum number of thralls you could own was 2. If you summoned two daedra lords later for example the two you had stored in your home in Whiterun would collapse into a pile of ash.

I resurrected the first two. I took them to Breezehome and killed them and their bodies just lay there. I went out, grabbed the vampires, came back and done the same. Next time I visited Breezehome... gone.

I would think that dead bodies, thralls or not, would despawn/disappear after a while.