Here is what I would do if I had a Confederate soldier to add to WikiTree:.I'd check out what unit they served in, go to records and find out which battles his unit participated in, then go to Wikipedia and find the battles and their alternate names. Yes, it's work, and I'd do this research myself. It gives me some background for the person's profile and I consider it part of writing a biography. I do the same thing no matter what war, using whatever records I can find and then checking National Archives for what's available there.
We don't have categories for every single battle, and we tend not to add categories for smaller skirmishes. The park service site has an extensive database of units, and in those pages, the battles are listed. Most of it is based on National Archives records and Dyer's Compendium. NPS database also includes units that have no description in Dyer's. I don't think it's necessary to repeat this information in WikiTree since it's already widely available, and my focus is the person's life, not the history of what was going on while they lived.
I've considered figuring out a category info box for units which would cover any country, any war, etc, but I'm not sure if it's feasible. In that, the aka could be used to add additional names, just like we do for cemetery categories. This would need to be thought out and discussed. I'm also conflicted about it, because every new template/info box, etc, causes suggestions, even the simplest ones like {{FindAGrave}} or {{CategoryInfoBox Cemetery}}