Monster Life reactions

The notice that comes up when you combine says that rank and level are factors in determining the outcome, but does the type of both combining monsters factor in as well? Will I have a bigger chance of getting a S rank ghost if I combine 2 A+ rank ghosts together as opposed to A+ ghost and some other A+ monster?

It should only factor into the type of the resulting monster, as combining two of the same ranks almost guarantees you the same type, whereas type A and type B could net you a type B or C. For example, I was dumb lucky today, fused an A+ Mushroom with an S bird, got an S Mushroom.