I'd suggest checking manga forums or dedicated Bleach fan sites. They often have detailed breakdowns and recommendations on where to pick up after a specific part. Sometimes, the author or official sources might provide cues as well.
Honestly, I don't know when the TYBW manga starts. But you could search manga databases or ask in manga enthusiast communities to get the details you need.
The TYBW arc's starting chapter isn't a straightforward answer. It could be different based on the manga version and region. I suggest looking at dedicated manga websites or asking fellow manga enthusiasts for the exact chapter.
Definitely Orihime. She is the type who would be easily attracted to Goku's pure - heartedness and his determination to protect. Her own insecurities might be soothed by Goku's confidence. Rukia, with her sense of duty, could find herself drawn to Goku's selfless acts of heroism. And Neliel could also be part of the harem. Her child - like form and yet powerful true form would create an interesting relationship with Goku, as he might be protective of her in her child form and respect her power in her true form.