absolutely. I'm in the tank right now trying to make it function. I'm prioritizing flash for colorless spells, but also considering dumb stuff like imprinting things like shields of velis vel on isochron scepter to have a copy effect on a stick.
Eldritch immunity which is included in the precon has the same use case, plus protection from colors. Cool that there's technically more than one eldrazi instant at one mana though.
You are missing the trick. Cast eldrazi that makes two eldrazi spawn on cast. Cast tribal instant. Copy original ulalek trigger with second ulalek trigger and use copies of spawn triggers to pay. Repeat to make infinite eldrazi.