Blue layer+ blue layer will only make blue layers, also blue+ white layers will get blue.
I think everything else would make green, but unless you have real Ameracauna, you might get green from their daughters.
Legbars have blue egg genes, the marans/legbar cross would be an olive egger, mix that with a blue layer and the resulting hen chicks will lay a mint green, mixe with a brown egger and the resulting henchicks would lay an olive tone.