Advice on my Mythic Spread

So this is what I have for my mythics. I have my favorites stared and those are my focus. I am currently just playing in normal. I'm being out DPS by same level and unsure where I am falling behind. I like my Bomba, and he has an air attack now. I've paid a little money, but nothing over $100.

Typical game play is start, level up normal, epic, two summons level, roulette epic, free summon, then either summon 10 if I failed roulette, or wait until wave 10 to max summons level then fill board. I spend a majority of my lucky stones on epic roulette (25% base chance) and buff legendary level once I have 2 or 3 out and alternate.