It's mainly because fan art often involves visual reinterpretation and can sometimes fall under fair use, while fan fiction typically involves extensive use of the original story and characters, which might infringe on copyright more easily.
Their relationship would likely become more intimate in a different way. There would be a deeper level of trust and reliance. Ichigo would see Orihime in a new light, as the mother of his child.
I'm not sure about a specific 'Ichigo and Orihime lemon fanfiction' title off - hand. But you can often find great ones on fanfiction websites. Just search for 'Ichigo Orihime relationship fanfiction' and look through the results. You might have to sift through a bit to find the ones that are well - written and suit your taste.
Fan art by Sarah Tregay is likely to be artworks created by her in the context of being a fan of something. Fan fiction, on the other hand, is fictional writing by fans based on existing works. For example, if Sarah Tregay is a fan of a particular book series, her fan art could be illustrations of the characters or scenes from that series. Fan fiction could be stories that expand on the plot, create new adventures for the characters, or explore different relationships within the world of that book series.
Yes, they seem to like fan - made art. They often share and respond to fan - made art on their official social media accounts, which shows that they appreciate the efforts of their fans.
Ichigo could start to take more interest in Orihime's hobbies and vice versa. This would show that they are not just a couple who love each other, but also friends who want to know each other better. For instance, if Orihime likes cooking, Ichigo could start to learn cooking from her and they could have some lovely family dinners together.
There's a fanfic called 'The Bond of Hearts'. It's set in an alternate universe where Ichigo and Orihime are childhood friends. It shows their relationship evolving over the years. It delves deep into their emotions and how they gradually realize their love for each other. The character development in this fanfic is quite engaging.