Hi! Thank you for the comment and the questions. Since I was a bit constrained by the rules of the jam some of the details were left up to interpretation and negotiation, but you got most of it right! Now, for some clarifications:
1. Yes, you can stack up training so potentially you could have a d12 ranged mounted beast for 14 points but that's a bit of a glass cannon and a lot of points in one basket, so, a bit risky (but fun if it works).
2. Ranged combat is the part that needs clarifying the most and a lot of the details I thought were cut for brevity so it was left up to the table to make it work, but I'm mentioning how I conceived it: In ranged combat the die becomes a sort of HP tracker, so a big die can get pinged down by several smaller dice. Since the turns work by "I go you go" with each piece, a bigger die can only respond by engaging in melee to one die at the time. I've also toyed with the idea that after melee/ranged combat the roll becomes the new HP (rather thank keeping one die for HP tracking and one for rolling) to represent the uncertainties of combat and make it more risky for bigger dice but it might too swingy, I'd have to test it more.
3. -1 melee means that they subtract a 1 for the contested roll if they get into melee.
4. Below 1 dies means that yeah, if the attack is higher than current HP the piece is removed. I specified it so it was clear how ranged combat works as a "chip away" roll and not a contested roll, unlike melee.
I hope this information helps! I am planning of making an expanded version of the game with a more delineated combat and some extra rules somewhere in the future but in the meantime ask away!