1. DEFINITELY YES
2. Planned
3. I’m not sure I understood the question correctly. But the plans include not only body parts growth.
After the release, I’ll have to deal with the bugs, and then the interesting stuff will start.
By the way, are you going to add height potions, lactation potions (Another way of gaining milk), and multibreasts potions? Will there be a feature to increase (or remove) the cap for body parts or possibly as an option? And one more thing, will you be able to gain a (Possibly permanent) buff upon using certain potions? EX: Like using a Fitness potion increase your speed and how long you can run?
Regarding the size changing potions: it's very complicated, both technically and from a game design perspective. Just think about it: entering buildings, syncing sex animations - all of that is tied to character size. I do have a few ideas about it, and I personally really want to see it in the game, but I'll be straight with everyone - I have no damn idea when I'll be able to implement it.
As for everything else : it's already in development. For example, right now I'm working on the combat system. Buffs from potions could follow right after that, since they're logically connected.