If you end up with Deathwing and Mecha’thun in hand at the same time you are screwed.

2 UI is just for faster cycle. Maybe it backfires occasionally but most of the time you’ll probably want to use both to burn your deck as fast as possible. It’s a theorycraft anyway so maybe 1 UI will be better in practice.

I don’t think you can combo with Biology project since you can’t have 11 mana.