a) I think it might not have been eating inputs necessarily, but my computer sometimes gets a significant amount of desync between pushing a button and the game actually receiving it. have you implemented e.g. coyote time and jump buffering? those might both help the situation.
b) The issue was mostly releasing the button after landing on a bird and then sliding off anyways. Perhaps platforms could have increased friction close to the edge, if you're not trying to move in a direction? Alternatively, if momentum is always preserved in air, that definitely needs a tutorial, since it is nonstandard to platformers. Had I known that were the case, I would have released the keys midair and this would probably have been less of an issue.
Hope this helps!