“What would be the best way to save all of this, for each player, besides a massive save file with the player name?”
I would argue that the best way to do this is using a nice plugin that I’ve built to do all that automatically, without any coding required; the plugin is 4.9 and 4.10 compatible, you can take a look at the tool here:
LINK
However, uncompiled plugins require you to have Visual Studio 2013 or 2015 installed (or XCode).
If you work on a Blueprint only project and don’t use Visual Studio, your best bet is to do what you describe yes:
Saving everything manually into a .sav file for your game. Like docs describing it here:
DOCS