Default -> alternative -> choice is indeed the better choice if it's not breaking compatibility.
The implementation of “✔/✖” works great, but maybe put the checkmarks in green/red too. While those are mostly universal I seem to remember some countries like Japan use both ✔ and ✖ as a negative(as in "incorrect"), so putting them in green and red respectively should help clear that situation(if it arises at all- I might be wrong about the whole Japan thing).
Anyways, great work. The engine turned out pretty nice and while some elements like the reward systems can use some light rebalancing I can honestly say I'm pretty happy with the result. It's by far the best small RPG engine out there and definitely the most user friendly one.