WW1 Low poly characters

So I’m working on this pack for the UE4 marketplace, I’m pretty new to characters and would love some feedback on faces. Here are some concepts I’ve got:

My plan is to settle on a face and use it for all the characters I’m going to make, I will make different facial hair styles to pick from. What I’m mainly concerened with is the faces, I’m trying to achieve a look that is kind of stylized, but tasteful. Any feedback is welcome!