MTG Salvation

Morph variant isn't within listed color identity. (Mono-Green)
Walker: This is going to be immediately taking over the game if you untap with him, but 2 toughness makes it just viable enough for stuff to get around indestructible to pick him off. on the flip it's pure gas, +6 power and trample is completely absurd, and his plus will always find you a dude if there's anything to find. Flavor is on point here as well.

Morph: I really like the idea, given how I took a similar line. That said, because of how turning instants and sorceries face up currently works with the rules the card as it stands today doesn't work:

Quote from Gatherer Rulings »

There are no cards in the Fate Reforged set that would turn a face-down instant or sorcery card on the battlefield face up, but some older cards can try to do this. If something tries to turn a face-down instant or sorcery card on the battlefield face up, reveal that card to show all players it’s an instant or sorcery card. The permanent remains on the battlefield face down. Abilities that trigger when a permanent turns face up won’t trigger, because even though you revealed the card, it never turned face up.

However if we assume that your mechanic was printed we also should assume the CR would have a corresponding update to allow it to work. As far as the card itself it's nice, but maybe a bit too nice - for your opponents anyway.

Both cards are within listed color identity (colorless)
Walker: This takes a bit of setup to really go live, but once it does you can really get some dumb things going. I do wonder if it's too prohibitive to get going though, seeing as you can't use artifact tokens to get the job done. Sure you'll get the artifacts back eventually...but is that too late to matter? He isn't flipping until turn 9 at the earliest, and 4 more turns to ult.

Morph: In interesting twist on bestow, where you can pump your team and not get 10-for-1'd by an untimely edict. It also makes it less favorable to kill the creature with the morphs on it, since they'll all flip. I think this is sneaky powerful and will be slept on until someone breaks it.

Both cards within listed color identity (Mono-White)
Walker: Naming is a bit too on point for my personal taste. Also most introductions to walkers use their full given name in their initial card, and I'm a bit sad to not see his family name (MTG Wiki says it's "Verada") on the flip side. As far as the card itself...you're going to have a really rough time flipping him safely, and even when you do he's...just okay, not really amazing. Would not exactly be thrilled to see this as a mythic in my pack.

Morph: "Geomorph" to me implies this mechanic cares about lands, not creatures. Even with a full field this is costing 5 to morph and flip, very often it'll be cheaper to just rawdog it unless you're really mana-pinched. The effect is cool and makes flavorful sense, but the card's just clunky all around.

Both cards within listed color identity (Simic). Submitted after the listed deadline, but there's been precedent for allowing entries a little late and you're doubtlessly busy juggling two sites' CCC loads. It'd be wrong of me to hold that against you.

Walker: Unlike Teyo we don't have any hint of family name for Tamiyo, so as much as I want to see a walker card with her full name we won't get it. Power-wise she's solid on curve, but there's no way to help herself flip built into the card, and 8 cards might be a lot to get to without help. Flip-side, making Ophidians has a lot of upside, and the ult is just back-breaking without being too hard to hit from starting loyalty. This is powerful, but not TOO powerful.

Morph: Going back to the suspend well, I see. That you can suspend it face-down turn 1 gives you a surprise factor that can really put some big things into play under the radar, and there's an obvious benefit to doing it this way. The card is fine, I really like the flavor and mechanics interaction, but it still feels...kinda clunky. Templating is also off for suspend's reminder text.

1st - Subjet16
2nd - void_nothing
3rd - IcariiFA

Eventide not only made a card outside the challenge criteria, but the morph card under today's rules doesn't work (and that's why I specifically worded my variant as a a replacement effect so the game never tries flipping the spell face-up and encountering that weirdness). Nice cards but an easy decision to put in the basement.

Lord of the Manor 1BB
Legendary Creature - Human Advisor (M)
Whenever a creature you control deals combat damage to an opponent, that player exiles a card from their hand. If four or more nonland cards are exiled this way, exile Lord of the Manor, then return him to the battlefield transformed under his owner's control.
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Davriel Cane, Kessig Diabolist
Legendary Planeswalker - Davriel (M)
+1: Discard a card. If it's not a land, exile it instead.
-X: Choose target exiled card with converted mana cost X. You may cast that card this turn, and you may spend mana as though it were mana of any type to cast that spell.
-7: Destroy all creatures. For each creature destroyed this way, create a 6/6 black Demon creature token with flying.
3

Source for naming conventions: https://mtg.gamepedia.com/Davriel_Cane

Endanger BB
Sorcery (U)
Soulcast (You may cast this card face down as a 2/2 creature for 3. Turn it face up any time by paying life equal to its converted mana cost. If it's an instant or sorcery, reveal it and cast it without paying its mana cost instead of turning it face up.)
Target player discards two cards unless they discard a creature card.