Definitely Hermione. She is smart and would be able to help Ichigo understand the complex magic world. Also, Hagrid. He is kind - hearted and has a lot of knowledge about magical creatures, which could be useful for Ichigo.
Kisshu and Ichigo are likely characters from a particular anime or manga series. They are the main focus in this fanfiction where the situation of pregnancy is involved.
Obviously, Ichigo and Dark Ichigo are the central characters. Ichigo, with his complex personality and powers, is always a key figure. Dark Ichigo, being his inner Hollow, brings a lot of drama and conflict. The OC also becomes popular depending on how well - written they are. If the OC has unique powers or a really interesting backstory, they can gain a following among fans of the fanfiction.
Ichigo and Tia could be characters from a specific anime or manga series. Without more context, it's hard to say exactly which ones, but they're likely to be characters with unique personalities and abilities that fans have decided to pair up and give a baby in this fanfiction.
I think his family would be the first to help. His sisters could bring him cold compresses to reduce the fever, and his father would use his medical skills. And from the Soul Society, Renji might come to check on him, as he and Ichigo have a sort of friendly rivalry. He would want to make sure Ichigo gets better soon so they can have their next sparring match.
Ichigo could meet Frodo Baggins. Frodo, being from a very different kind of world, would find Ichigo's situation strange. But they could bond over their shared sense of being out of place in some ways. Frodo could teach Ichigo about the importance of perseverance in the face of great odds, and Ichigo could protect Frodo from any potential threats in this crossover world with his swordsmanship.
Maoni's wife was from Daqing, Hei Long Jiang. However, his wife's name was not mentioned in the search results. Therefore, it was impossible to determine who the fishy wife was.
Rukia could be a character. She might come to Ichigo's rescue when she hears about his situation with the tentacles. She could use her own powers to freeze or cut through the tentacles. Another potential character is Uryu. He could use his Quincy skills to disrupt the energy of the tentacles. And there's also Orihime, who might use her shield - like abilities to protect Ichigo from the tentacles.