The database is user maintained, so some things may get missed, and somethings take time.

Upgraded users can add and fix cards themselves. Otherwise, your best bet is to post here in the official missing card/token thread.

They uploaded their Amonkhet pre-release deck, so it should be legal.

Short answer is TappedOut has been known to have legality issues for a long time. It's because the database is user curated, and requires time to deal with these things. You just need to make specifics known, and eventually someone will get to it. You could always upgrade your account and fix stuff yourself!

Diregraf Colossus. Don't worry about filling the graveyard for the first ability, just worry about casting zombies to make more zombies. I've pumped out swarms with that guy in the past.

Graf Harvest is awesome too. One mana to make all your guys harder for them to deal with is a nice price. If you're planning to attack that is.

Ah okay. Now I see that they're all rates. Interesting. Hopefully it won't lead to a seeding issue where the boxes are easily mappable.

Is there still going to be a double-faced card in every pack?

Learning experience.

Flavour-wise I don't like it. Doppelgangers because of "reduced complexity?" The player/Walker is now summoning illusions/representations of walkers instead of the actual 'Walker.

Functionally I think it strengthened the card type, and I think it's allowed for less planning on deck building. Before you may want to limit the number of slots dedicated to 'walkers to limit the number of times you end up with dead cards in hand. Now there's less concern of that.

Overall I don't like it, although I will adapt to the potential. We'll see what happens.

My Edgar deck is the same, but definitely is not top tier.