He could interact with characters from the crossover world who are used to the concept of motherhood. For example, if it's a crossover with a fairytale world, he might interact with fairy godmothers who could offer him advice on how to be a good mother.
Well, perhaps in this fanfiction, Harry is in a crossover with a world where family and motherhood play a crucial role. He might become a mother due to some sort of curse or magical experiment gone wrong. As a mother, he would have to learn how to cook, clean, and take care of children, which is a far cry from his usual adventures fighting dark wizards. He would face challenges like dealing with the children's schooling in this new world, and also protecting them from any threats that come their way. It would be a story full of growth and self - discovery for Harry.
A potential crossover could be with the 'Lord of the Rings' universe. Harry, as a mother, could find themselves in Middle - earth, perhaps with their child being a key figure in the fight against Sauron. Another could be a crossover with 'Star Wars'. Imagine Harry, as a mother, on a far - flung planet in the Star Wars galaxy, trying to keep their child away from the clutches of the Sith or the Empire.
Hermione is usually one of the main characters that interact with Harry. She might be in awe of his new powers at first but then help him use them wisely. Ron could also be there, perhaps being a bit more skeptical at the start but eventually coming around. Dumbledore might also play a role, guiding Harry even in his god - like state, sharing some of his own deep knowledge of magic.
He could interact with Iron Man. Iron Man would be curious about Harry's magic and might try to incorporate it into his tech somehow.
Obviously, Buffy would be a major character he'd interact with. They could start off as wary of each other but then grow to respect one another's fighting skills. Giles too, as he has a wealth of knowledge about the supernatural, and he and Harry could have some interesting discussions about different types of magic.
The characters could interact through magic exchanges. For example, Hermione could be fascinated by the magic of the ponies, which is so different from the wizarding magic she knows. She might try to study it and figure out how it works. In return, Twilight Sparkle could be interested in the books Hermione reads and learn about wizarding knowledge.
The characters could interact in various ways. For example, Merlin could meet Hermione. Hermione, being very interested in magic knowledge, would be fascinated by Merlin's different approach to magic. She might ask him a million questions about his spells and how he learned magic in his time.
Some fanfictions might choose Hermione as the mother. This could create an interesting dynamic, as Hermione is Harry's best friend. It would bring a whole new set of relationship developments and challenges for Harry as a father.
One character could be Dobby. Even though Harry is living alone, Dobby might still find a way to visit him and offer his help. Another could be the Hogwarts ghosts. They can pass through walls and might visit Harry in his solitary abode.
Obviously, Hagrid could be one. He would be so amazed and probably take baby Harry on little adventures around the Hogwarts grounds, listening intently to what Harry has to say.