In Xcom: Enemy Unknown (2012), can I change tactical game saves to modify loadout?

I just started the Temple Ship assault (the last mission), and I'd like to modify the loadout of one of my soldiers. Unfortunately, I don't have a save I can rollback to before the squad left the base, so I can't use the normal loadout editing. It was a dumb mistake made at 3 in the morning that I left with the wrong loadout, so I really don't mind "cheating" to fix it.

I've looked for mods like ToolBoks, but it appears to be long-since outdated and unsupported. I'm not aware of any others that may help.

I've also unlocked the developer shell / console, and have played with it some... but it looks like most of the commands for giving weapons or items are for the strategy-side of the game. If there's a command that can help, I'm all ears.

I'm also mildly comfortable with a hex editor, so as long as I know where to look to change the values in the save file (and what to change them to), I'd be fine.

So does anyone know how I might accomplish changing the loadout of a soldier once a mission is in progress?

About your main question. No you can not edit the saves to change the loadout of a soldier or anything for that matter. The ToolBox is too old and works erratically most of the time now. Some of its feature work properly but some doesn't work.

As for going back to save, usually there is a autosave of mission control room before you launch any mission. So you might want to go back to it and restart the mission. If that has been replaced then I am afraid you have to go further back to your newest save before that particular mission and replay those missions.