Re: diy wooden squat rack with pull up bar
I would rate kipping pull-ups as a 3 out of 10. It's something you'll learn fairly early in the progression of skills, though not a super important skill. I would recommend you be able to do 5 or more unbroken deadhang pull-ups before you go to kipping.
I've never seen a combo stall bar / squat rack, as the worlds of gymnasts and weightlifters are not often this close. It's an interesting idea.
What you're describing sounds like you'd put the stall bars in the same vertical as the squat rack. I wouldn't do it that way unless you're okay taking the time to switch things out a lot.
Stall bars only need to be a couple inches from the wall - enough for fingers to grip inside the bar, or for a toe to hook inside the bar. I would recommend building your stall bars close to the wall, and having your squat verticals away from the wall. A lot of CrossFit gyms have a wall mounted pull-up/squat rig with wall ball stations inside the rig. Think of your rig as having a squat/pull-up station a few feet from the wall, with the stall bars inside the rig, close to the wall, in place of a wall ball station. This design however, will double the number of 4x4 verticals you'll need.
The space to get under the bar would be less relevant than the space needed when using the stall bars with this design idea.
If you separate the stall bars and the squat rack, your girlfriend and daughters could be doing their thing 5 seconds after you're done squatting, or maybe even at the same time.