I probably wouldn't play stillness, as it causes you to lose the battle. Using just Jubilee would probably be better, and, if you plan on using joseph, you can also use Sword of the Lord and Visions, which are both green side battle cards. then, you can also throw in ethan or Cloud Daniel so you can get some of the green side battle stuff back. something else to consider throwing in is a clay missionary and Epaphroditus. He's a territory class hero who says while you control a missionary and no hero is in battle, restrict opponents from playing evil enhancements. pretty solid combo if you want to make a deck based around side battles. And, If you would like to go the clay route, there's always faith of gideon if you want another side battle card.
oh, and also, no, that doesn't break any game rules. Seems pretty solid to me! Good luck!
