The idea was that writing "SandWing" in every SandWing's Creature type would make the creature type squashed. This allowed me to keep the flavour of the different tribes. If I make another SandWing (e.g. Qibli) they will have Poison Barb too.

Feels very blue. Very weak overall. At mana value of 1 you could get Faerie Seer or at least Silver Raven, or if comparison expanded more loosely then cards like Snarling Gorehound and Barrier of Bones with surveil which is generally stronger as it enables graveyard synergies.

That doesn't seem like the type of thing you would want to keyword. The point of keywords is that they are a repeated mechanical pattern that players can mentally shortcut after seeing and playing with cards featuring it for a while.

This ability would be extremely oppressing in larger numbers and lower cost cards, making it unfit for prominent use, especially at lower rarities - which are what keywords are generally meant for as they lessen the overall mechanical nuance and complexity by generalizing/standardizing abilities and lowering the amount of raw rules text (where reminder texts don't count).

I think what you might be looking for here is a 'flavor word' as seen in cards such as Air-Cult Elemental and Blink Dog.

Well, that's comparable to fog bank. Definitely can't be common

Yeah, this at least chump blocker that only dies to board wipes, which is crazy.

Seems kinda op and especially problematic at common. Reminds me of Order of the Stars.