I'd drop x1
Island and x2
curse of the bloody tomb in favor of x3
Oblivion Ring, while this may seem like it's a bad idea given that you'd be cutting one of the cards that actually mills your opponent, you have to remember that Milling 60 cards usually takes longer than dealing 20 damage, as such it's important to be able to slow your opponent down as much as possible, hence why walls are such a good idea.
The island is because I can't really see anything else I'd rather cut, most of your mana ramping comes from searching for lands rather than drawing them so having one less island won't be very detrimental, also your mana curve is pretty low and there are only a couple cards that you have that need a lot of mana (
Sands of Delirium and
Increasing Confusion) and most of that mana should be coming from
Axebane Guardian not your lands.
All this being said I would still strongly recommend
Fog if you're planning to play at FNM, Zombie decks won't really care about losing part of their deck, they're very fast and will be able to kill your walls faster than you can put them out, fog could buy you that extra turn or two that you need to establish a defensive base to lock them down. If you're just playing with friends this should be perfect, I really like this deck by the way it really takes advantage of several mechanics, I'd never have thought that Green, Blue, and White Mill could be a thing