Hi Aditya Sriram!
I like your version of Mixed Levels and as for my version, I would do the same idea as you but keep on adding every NEW Mixed Combination level type!!! (I hope you don't mind me repeating everything you just posted as I add in more details to each of them.)
(*) = …in a certain amount of moves!
Gap = The amount of levels between the previous and the next 1st Mixed Combination Level.
That was just Part 1 of 3 for Mixed Levels of my version! Part 2 is shown in a different comment!!