Do I have to finish my basement walls with drywall?
All building codes in the USA and Canada specify that plastic insulation (EPS) must be covered by a thermal barrier equivalent to 15 minutes of fire protection in habitable spaces. If the basement is classified as habitable space, then gypsum board must be applied but does have to taped and filled. Check with your local building official.
Can masonry be installed on the exterior walls?
Yes, Fox Blocks has a brick ledge form and the xLerator ledge reinforcement that is designed to support masonry. Fox blocks also has a tieKey accessory which is a specifically made as a masonry tie, to be inserted through the form into the concrete.