Home is built in 1888 in NE Wisconsin. Gutted out the living room due to 2nd story bathroom leak prior to buying it. The room is around 24x35 with a 9ft ceiling. Once the wire/plaster combo was removed, I lost 1.5" of wall thickness which will have to be furred out to meet finished flooring. The siding has 1.5" foam board behind it. My questions are these:

1. Can I get away with R19? All the framing is 2x4... If I fur out the studs 2 inches could I use R19(6")? instead of R13(3.5")

2. If I do fur out and use R19, could I simply run the electrical between the strips of furring (in front of insulation)?

Thank You