Moisture barriers when finishing a basement?
I would NEVER put up plastic on the outside basement wall. All you will do is trap the moisture in the wall and create an environment perfect for mold. Especially with batt or blown insulation behind it.

EPS actually breathes water vapor and is better than standard insulation for vapor passage.

Moisture from the wall has nowhere to go but through the wall and needs to dry to the inside. The ground outside is already full of moisture so it can't dry to the outside.

Check this website here.

Read the various articles on vapor barriers and mold. These articles are written by experienced individuals, some with PhD's in building construction like this guy.

These people know a lot more about construction than any site I have ever seen.

Good Luck!