I actually love the idea of her getting small buffs when her mines are destroyed it would be a pretty easy way to make her mine cards useful without overbuffing her and it would be pretty neat maybe make her mines target 2 or 3 people at base and give her mines a health card, and a heal card upon destruction like you said. even a card that lowers teleporter cooldown upon destruction would be nice
or an ult charge card upon destruction so your enemies can take out her mines at the penalty of giving her a small amount of ult charge.