However, there might also be some who are a bit skeptical. They could worry that he might misinterpret some of the fanfiction or use ideas from it in a way that the original writers don't like. But overall, I think most would be positive as long as he respects the fanfiction world.
For Michael's family, if they have been in hiding or trying to keep a low profile in Roswell, the pregnancy could be a big threat to their secrecy. They might be hesitant to get involved for fear of attracting unwanted attention. Maria's family, being human, might have a hard time adjusting to the idea of having an alien - related pregnancy in the family. They could initially be resistant, but over time, with understanding and seeing Michael and Maria's commitment, they might come around.
Yes, in some fanfictions, Tanjiro is depicted as the reincarnation of Yoriichi. This concept adds an interesting layer to the story as Yoriichi was an extremely powerful and legendary figure in the original lore. The idea allows for new storylines where Tanjiro might inherit some of Yoriichi's skills or have a deeper connection to the past events related to Yoriichi.
Tanjiro's fate in the manga is that he ultimately passed away. This event was a significant part of the story's development and had a profound impact on the other characters and the overall plot.
Tanjiro's strength in the manga is significant. He acquires new powers and techniques, and overcomes numerous powerful foes with determination and strategy.