No to the diseases one... That's taken IIRC. In the taker ending, it talks of new diseases being created in the shaper-taker war, of plants dripping acid and all other sorts of hilarious stuff. The "last creation" of Eass is described as something WORSE.
Nah, it must be a path of research the takers abandoned, meaning it should be distinct from the other mad schemes they conducted. (eg. the Drakon chain, the geneforge, the beasties of inner ghazad-uss, the eyebeasts, the rotgroths, super/invincible spawners, war-bred serviles, spirit armies, reapers, stasis fields...)