Well depends on EE roo genetics… your green layer has brown genes and blue genes = green eggs, the Amerucana if she lays blue should have at least 1 blue gene and either another blue gene or white gene, if she lays a more green egg then figure 1 blue, 1 brown (brown genes way more comp,ex than that but keep it simple for sanity reasons)… so you should have then idea of what the hens contribute… now the rooster…
You will have to breed him to them to see… he could carry all blue genes, blue and white, blue and brown, all brown or all white… depends a bit on his line, like the hens in my picture are what people call EE but laid beautiful blue eggs I would be pretty confident a rooster from the same hatchery would have good blue genes…. But my first EE ages ago laid an ugly pale green, different hatchery so I would consider a rooster from them back then a total guess on what he would carry genetically.
So let’s assume though your EE has at least 1 blue gene… then you could expect from the hens, pullets capable of laying blue, green, possibly brown or even white eggs depending on his second gene if not blue… but if you luck out and he is double blue you could get blue and green laying pullets.
Breeding the birds is the only way to know for sure. I hope this helps.
PS if he is double blue egg gene bird, if he is paired with a brown egg laying hen her Pullets will produce Olive Eggers (1 brown, 1 blue gene).