Spoiler for Quote from ZephyrPhantom:
As a reminder:
Please note that to be completely vanilla, the creature cannot have any abilities whatsoever (active and/or passive).
This guy gets it.
Airborne is vanilla.
That's like saying a Normal Pendulum Monster with a spell effect is vanilla, IMHO. The moment it gains an an ability like that, it's "French vanilla" and is still an ability, even if it's not an active one. Having an ability defeats the idea of being vanilla IMHO.
(Compare: One could argue Pest without burrow/ in mono 
is "vanilla" because it only has a passive. However said passive is also the central part of using it and drastically changes how it is played.)
5|7 / 7|7 for 5 Gives Life a non-dragon creature that's durable
7|3 / 7|5 for 6 Gives Air an affordable midhitter that doesn't require upkeep, stats lower than other elements because SoFr (or is airborne not vanilla? That's a bit restrictive. In which case this could have better stats & be air's non-airborne creature)
5|0 / 6|0 for 1 enables a fast nightfall rush (darkness generally lacking speedy options)
5|2 / 7|2 for 4 allows a more fire heavy immorush compared to golem, or non-immo less dommy mono fire
could probably benefit more from a pseudovanilla card that had some sort of ability - e.g. a 6 | 6 that could be sacrificed to disable a shield or something like that. I think we'd be wasting this card slot on a vanilla, if anything, given Life's already high amount of vanilla creatures.
Airborne would go against true vanilla, IMHO, for reasons stated above. And even if it was airborne, why would monoair want to use it? Dragonflies/Wyrms deploy faster.
This is the only one that I think actually has no redundancy or role issues.
- Fire-heavy/monofire immorush already has Phoenix which also fuels more Immos. Golem works fine because it drains excess 
that would otherwise typically go unused.
1. I would argue that airborne is not an ability, but a trait, just like attack, health, element, or attribute. It's a natural part of the creature. Saying airborne isn't vanilla is like saying that Bone Dragon isn't vanilla (in addition to airborne) because it's buffed by Nightfall and harmed by Holy Light, or that Sparkman isn't vanilla because it's an Elemental Hero. I'll make a comparison to health. You can say that airborne lets a creature go through Wings, but having high health means a creature is stopped by Gravity Shield. You can take away airborne, but you can also take away high health. I believe that airborne has this misconception because it was added to the game long after launch. If all cards were originally not divided into elements, and then zanz divided them, people would say that only Other creatures were true vanillas. In the link you gave, French Vanilla would be cards like Immortal and Sapphire Charger. They do have rules text on them, but only an explanation of the mechanic like all Magic mechanics had when they were introduced, and shown to be unnecessary by Chimera.
2. I don't think it's likely that you can make a vanilla that can't be improved by adding some sort of ability, no matter how insignificant. Nobody would argue that the spiders/recluses were better cards before they were given web, but that doesn't mean they were badly designed cards before. Ghost of the Past would still have had a strong impact on mono time if it was vanilla. The point of the challenge is not to design the perfect vanilla, but to see what you can create and what impact you can make on the game with a very limited design.
3. I dig the avatar.
