Some characters from Fma would approach the magical creatures with a sense of wonder and a desire to learn. They would try to find alchemical explanations for their abilities. For instance, a character might see a Phoenix and wonder if its ability to be reborn is related to some form of alchemical regeneration. They would also likely compare the magical creatures to the chimeras and other strange creatures they are familiar with in their own world. This would lead to some interesting cultural exchanges between the two universes as they try to understand and interact with the magical creatures.
For the FMA characters in the OHSHC world, you can show how they adapt to the new social norms. Edward, for instance, might initially be frustrated with the elaborate social games in OHSHC but gradually learn to play along. You can also focus on how their goals change. Maybe they start off trying to find a way back to their own world but then become invested in the problems of the OHSHC characters. For the OHSHC characters in the FMA world, their charm could be used in different ways. Tamaki could try to use his charm to negotiate with the military in FMA.
Edward's alchemy skills and Harry's magic could combine in combat. For instance, Edward could transmute the environment to create barriers or platforms, while Harry uses spells to attack over or through these structures. Hermione's knowledge of magic and Edward's knowledge of alchemy could lead to some amazing new discoveries. They could combine their research skills to find solutions to problems that neither world has faced before.
Edward Elric is often a popular character. His brash and determined personality can create some really interesting storylines when combined with the world of High School DxD. He might get into all sorts of trouble or challenges with the devils and other characters there.
Overall, the FMA manga set is quite complete. It includes all the major plot points and character developments. However, there might be some minor variations depending on the edition or printing.
The unique characters and their humorous interactions in fma comics often bring the laughs. The unexpected plot twists and comical situations also contribute to the fun.
I'm not entirely sure specifically about 'fma visual novel' as there could be many visual novels with that name or abbreviation. It might be related to the 'Fullmetal Alchemist' (FMA) series, in which case it could be a visual novel that tells a story within that universe, perhaps exploring different storylines or character relationships from the original anime or manga.
I'm not sure specifically if there is a publicly available 'fma riza pregnant fanfic'. You could try searching on some fanfiction websites like Archive of Our Own or FanFiction.net.