Sure. Fanfiction often thrives on unexpected combinations like 'toph vs edward'. The great thing about fan - created stories is that they can take the characters in new and exciting directions. For example, they could be in a battle of wits or a physical fight in a completely different setting than their original stories. It's all about the fans' imagination, so there's a good chance there are some great 'toph vs edward' fanfictions waiting to be discovered.
Archive of Our Own (AO3) is a great place to start. It has a vast collection of fanfictions, and you can use its search function to look for 'toph vs edward' specifically.
It's really hard to say. Aang was a very powerful Airbender and the Avatar. He had the advantage of being able to enter the Avatar State more easily due to his spiritual connection. However, Korra was a very physical and aggressive fighter. She had mastered all four elements and was not afraid to take on tough opponents head - on. In a fight, it could depend on the circumstances, like the location and whether they have any outside help.
One interesting plot could be a time - traveling scenario where Aang and Korra meet in a different era. They might have to team up to face a new threat that combines the challenges of both their times. For example, an ancient spirit that was sealed away during Aang's time is accidentally released in Korra's era, and they need to use their unique bending skills and knowledge to reseal it.
Since 'lemon' fanfic is inappropriate, we can't really discuss the characteristics in that context. But in general, aang is known for his kind - hearted and adventurous spirit. Toph is strong - willed and independent. In proper fanfic, these traits are often explored in their relationship, like how aang's optimism might contrast with toph's more cynical view at times.
Toph's age in the comics can be a bit ambiguous. Different comic series might portray her at different stages of her life. Generally, though, she's often shown as being in her youth, with her age ranging from around 12 to 20, depending on the context.
The 'lemon' aspect might be a bit hard to come by in a clean way as it often involves inappropriate content. But for normal Korra and Mako fanfictions, you could also try FanFiction.net. Some stories there might show their relationship developing, their adventures together, and how they support each other, which can be really interesting to read.
Korra could meet the founders of the different bending disciplines. She could meet the first water benders and learn about the purest form of water bending. This would not only enhance her own skills but also give her a deeper connection to her water - bending heritage.
There's a fanfic called 'Aang and Toph's Journey'. In this one, they face a new threat to the world and have to rely on each other's skills. Aang's airbending and Toph's earthbending work in harmony as they overcome obstacles. It has a really engaging plot.