I finished installing the styrofoam insulation board, and went back with some "Good Stuff" spray foam in a few areas (outside & inside corners, around the geothermal pipes), and then taped all of the seams.
Keith came over on Friday night and we got started on the framing. We must have mis-measured the first wall by 1/4" (too long), because when we raised the wall, it hit the joists with about six inches to go. I had to use my mini-sledge to get it flush against the wall. Not sure what happened...we measured first and left about 1/8 of an inch...but whatever. Let's just say that wall is...solid. It ain't goin' nowhere.
On Sunday, Teresa's dad came over and we put up four more walls...this time I measured again, and reduced the length of the studs by 1/4"...and they fit much better. It got a little goofy where the geothermal lines came into the basement, but after some planning, it turned out pretty good.