Great list! I normally play simic infect, but I quite like the added options you get by adding black. One suggestion, try Wild Shape instead of Snakeskin - it can give hexproof or make your 1/1 a 3/3 with trample, meaning you can use it both for attack and defense, I've had great results with it.
In match 2 you talk about not wanting to make your opponents murktide bigger with endurance. I might be misunderstanding what you are saying, but that's not how the interaction works. Murktide gets counters from cards exiled with murktide. But endurance isnt a murktide, and it also doesnt exile, it puts on the bottom of the library. So no need to worry there.
