I'm not sure this counts as it's not really something I didn't realize, just something I didn't think about cause you only really get the chance to 3 - 5 times. In the very first fight when you're fighting with all the house leaders, you can take the weapons and vulneraries of the ones you're not gonna pick.
Edit: Also, any save file with the Soothis logo is treated as a new game plus file so you can use them for a new playthrough. I.E if you're midway through another playthrough and it has a soothis logo, you can use it as a new game plus if you want to reset for whatever reason. The only thing that carries over from the currently playthrough of that file is time. Everything else gets treated as the previous playthrough *Confused wording is confusing* I.E If you're playing black eagles on a new game plus file that was blue lions before, it'll carry over everything from that blue lions playthough but it'll keep the time of the black eagles playthrough.
BE: 156:12 Keep
BL: 149:32 Lose