Why no negatives until week 8?
Because lowering your full bodyweight is harder than lifting a submaximal one. Doing them before you have hang and row strength is how people get sore elbows and stall for a month.
I don't have a pull-up bar. What now?
A doorway bar costs less than a month of gym membership and covers every exercise here except band-assisted work, which needs headroom. Rows can be done under a heavy table with a towel.
Should I lose weight at the same time?
If you have weight to lose, it helps a lot and it makes the strength work feel like it's paying off faster. Don't cut so hard that your sessions fall apart, though — you need to recover from them.
What if I hit it at week 8?
Then take it. Move to two or three singles a session, keep the rows, and start building toward five reps.