Definitely Shinji. He was at the center of so much in the original series, and after the 3rd Impact, his character development would be crucial to explore. He could be a broken, shell - of - a - person trying to find meaning again, or he could have newfound strength and purpose.
One idea could be exploring how the remaining characters rebuild society in a world forever changed by the 3rd Impact. Maybe they have to deal with new forms of life that emerged from the cataclysm.
Perhaps. The Evangelion fandom is known for its active participation in creating and consuming fan works. 'evangelion the one i love is fanfiction' could be popular if it manages to resonate with the fans' emotions and expectations. For example, if it delves deep into the complex psychological aspects of the characters, similar to the original series, it might gain a following. Also, if it provides a fresh perspective on the love stories within the Evangelion universe, it could attract a lot of readers.
In general, the Evangelion mangas are considered good. They expand on the anime's universe, providing more depth and character development. However, it depends on personal preferences as some might find the style or pacing not to their liking.