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.
It depends on the specific fanfiction. Fanfictions are known for their creativity and bending of established rules. While Naruto is a shinobi from the Hidden Leaf Village in his own series and Shunsui Kyoraku is a captain in Bleach, in the world of fan - made stories, the author may have crafted a complex and unique narrative where Naruto is indeed the son of Shunsui Kyoraku. Maybe there's some sort of magical or time - traveling element involved to make this seemingly odd connection work.
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.