bathroom shower in basement along foundation wall

I wanted to know what everyone things about how to go about this. I have the pan located in the basement the will intersect 3/4 of glass block window. I would like to keep the window but wasn't sure about going about this. The entire wall system will have 1" XPS foamBoard with a 2x4 wall with 1" gap from foam. I plan on using using 2 layers of 2" foam on lower 1/4 of stud wall and kraft faced on upper and no vapor barrior and using paperless drywall. The questions is about the window in the shower. I am going to frame it so it looks like in the pic but should I put a 30lb felt on before the durock and tile? I know that would be a double vapor barrier in that area. How do I get around sealing the window? I am going to tile the inside of the window. Do I insulate at all behind the shower wall? Should I just call it quites and cover the window? I wanted some natural light since it is a basement. Thanks everyone.