Could you name Sphinx's revelation for example and get two applied to X? Can you name a legendary enchantment creature?
{council of the absolute}
use the curly brackets ;)
You can't name a legendary enchantment creature (for example, {Heliod, God of the Sun}) because while it has some types that aren't creature, it is still a creature.
From Gatherer's rulings:
9/15/2013 The type-changing ability that can make the God not be a creature functions only on the battlefield. It's always a creature card in other zones, regardless of your devotion to its color.
Because it is a creature, you can't name it with the council.
I don't know the answer to your other question and after a bit of looking through the rules I couldn't find a ruling. I'm going to have to leave that one to someone else, most likely Testset. Sorry!
For the question about {Sphinx's Revelation}, yes. So you can tap 3 and gain 2 and draw 2, essentially paying {0} but it's considered {2}.