Just an idea for the summoning, Monsters who are 1 level apart (Lvl 3 + Lvl 4, Lvl 2 + 3 +4 for more advanced cases etc.), make them belong in the main deck? Pay x ammount of life to shuffle back into the deck and draw 1 card, can only use this effect once per turn. I kinda associate red with lp so a lp cost fits imo. Basically, Xyz monsters were doubles and triples, this'll be a straight with less cards (If you guys understand poker) So the highest monster in the chain would be the lvl of the summon. You could add specific types, like a lvl 3 + a lvl 4 fiend, or even Dark magician + a lvl 6 monster for Crimzon Dark magician? Could have them be the same type/attribute but i think that would be best as an option and making the overall summon way too difficult, they also wouldn't be usable in all decks.