In some fanfictions, Bakugo can become more empathetic. For example, if he experiences a situation where he realizes the pain he's caused Deku over the years. His aggressive nature might soften as he starts to understand Deku better. Deku, on the other hand, could become more assertive. Instead of always being the timid one, he might stand up to Bakugo more firmly in fanfiction scenarios.
No way. The manga portrays their connection through mutual respect and competition in their journey to become great heroes. A kiss is not part of that narrative at all.
One common theme is friendship. Despite their initial rivalry, fanfics often explore how Bakugo and Deku form a deep bond. Another theme is growth. They both grow as heroes and as people in these stories. For example, Bakugo learning to control his temper and Deku getting stronger.
At first, it could be extremely strained. Deku might be terrified of Bakugou and avoid him at all costs. But as the story progresses, if Bakugou realizes his mistake, he could start trying to make it up to Deku. Deku, on the other hand, might be hesitant to accept Bakugou's apologies at first, but over time, they could start to rebuild a more positive relationship based on mutual respect.