I can’t seem to visualise things well with my eyes closed. With my eyes open, I can see what I want to see in my minds eye but its more difficult with my eyes closed. Does this matter when I try WILD or any technique that requires visualisation?
It wont if where you sleep is dark, eventually during the visualization if your eyes are open they will close. 
WILD doesn’t require visualization. with WILD you just close your eyes and if you see something you try to focus on that, but you don’t need to visualize anything - it’s VILD then.
Do you need visualization for MILD?
No, not really.
There are some variations of it that you use visualization for though.