ok, for mill there are 3 things you need to consider; speed, repeatability, and blocking potential. speed refers to how many cards get milled at a time(1 per use is terribly slow even if the spell costs only
to play) and not so much when the spell/ability is used. repeatability, is if anything more important. if your mill is all in spells like dream twist
then the mill will wither and die before the game ends. the primary challenge is that you have to mill somewhere from 40 to 50 cards to win while the other guy only needs 20 damage or 10 poison counters to do the same. it's not terribly difficult if you can get the right cards and play smart, but it is still the harder win con to meet.
running a mill deck I'd build around jace's erasure
x4, mind unbound
and other draw options. this is how my mill deck works and is what I'm most comfortable recommending. there are plenty of ways to draw a lot of cards in blue, mind spring
on any unblockable critter, just to name a few. muddle the mixture
is good here since it counters and let's you search for erasures. if you can get them, surgical extraction
can be amazing in this kind of deck. simply wait until you've milled a really good cards then drop it for 2 life, and the better the deck the more targets this spell will have.
for blocking, some of the critters you've listed will do but what you really want is to be in the range of guard gomazoa
, wall of frost
, and belltower sphinx
. I would run red if, and only if, you want to kill off threats. thing is you don't really need to. spells like sleep
and vapor snag
when combined with a strong blocker line will last long enough to give your mill the chance it needs to win.