Great tweaks to minimize frustration and maximize the joy of battle.
An unrelated suggestion: automatically level down cards when higher levels activate an attribute that disqualifies the monster from a battle. For example, in the ruleset where melee monsters are forbidden, my chicken should level down to its pre-melee level. Taking this idea further, it should be possible to play a card at the level you own it or any lesser level. There should be an interface for leveling down cards when submitting to battle. This could be important for when speed is reversed or cases where level 10 is worse in health than level 9.