Maybe a silly question

I have never used the axon/DL3 before and am just playing around with one at the moment and have one or two maybe silly questions that I don´t seem to be able to find the answer for in the manual.
1. Does their give any type of blending modes between layers such as multiply, subtractive etc etc.
2 even when layers are keyed using intensity key or chroma key, I am still getting the underneath layer adding into the upper layer, just a tiny amount but its still not keying correctly. Is this normal?
Also when masking (layer 1 video, layer 2 "gobo mask " with intensity or chroma key ), its not keying out the masked layer 100 %, Its still visible outside of the "mask", dark but visible.

Thanks for any answers.

DP