For Alola forms, I was trying to pick something that particularly set them apart from their regular form, because otherwise they might as well have the same HA (as I did for Exeggutor and Raichu). The strong jaws that Rattata and Raticate clearly have are present across both forms, so I see no reason for the Alola form to get it when the regular one doesn't. Thus, I went for something that makes a lot of sense for Rattata's Alola form backstory, where it fetches food for Raticate, and based Raticate's on its new design.Ok, just a couple things. First, Rattata-A and Raticate-A should definitely get Strong Jaw, but that's just my opinion.
Second, I find it odd that you give the base stage of all three starter line a different Ability than their Evos, as that is atypical (only the Tepig line changed their HA while evolving, and even then it only happened during the transition from Pignite to Emboar.)
It is atypical for starters, but it is normal for many other Pokemon's HAs. The ones I picked make perfect sense for the final and mid stages, but none make too much sense for the basic stage. Rowlet is not yet associated with projectiles, and so doesn't fit Sniper until it starts throwing darts. Litten doesn't have the physique for Sheer Force before it gets Torracat's beefy arms. And Popplio makes no reference to dancing in his dex entry, whereas the other two stages have it as a primary focus.