Yeah I had a read on your post on the separate tech trees, think it would be especially nice idea for the mission where aldarisis takes over your Templars. Also believe tech is a lot different for UED, but i do not know that much about smaller bits of lore. I dunno how useful I would be for a project like this because haven't done something like this in the editor before. An idea for the Zerg would be; in hots abithir(if that is spelt right, the guy who changes the Zerg strains) tells kerrigan that he was created by the overmind then also captured again by Kerrigan after the overmind was killed, so he might be able to be incoperated somehow.
Also I've read about these episode 1 Terran campaigns that are mentioned supposedly left onto earlier copy's of a disc but not officially in the campaign, perhaps those could be worked into this.