1.) We all choose the breedings we're going to do. I trust that the mod making the offspring will take the Impel Liqour in to account and think about if they'll be there to grow them. That's also why I said 2-3 days rather than a specific day number. But yeah. We all choose the breedings we do, so I'm sure people won't pick ones they can't grow on time.
2.) I saw a few people mentioning in the irc that they like small litters, especially for things like lifemates and not wanting certain pets to have large lines, ect. I don't see it as a potion that is used often, but some people do seem to want small litters in some cases, so I made a cheap potion for when they do.