Doing that in a raw JSON file is pretty tough - it's hard to even find the latest version. Editing the save could mean just stomping on the latest history frame (rewriting history) or creating entirely new frames.

There are N copies of that soldier, all representing different history states of that soldier throughout the game, and the only one we want is the latest one. From the above example, there isn't just a single object with the info for one of your soldiers. So just deserializing that out into JSON file or a GUI app isn't enough, we really need to reimplement the history management system in some form. An XCOM2 save is basically a dump of the history. If you've done any XCOM2 modding you know about game States and the history. That isn't how XCOM2 is organized at all. Or design a GUI app that does that for you. It's just a matter of knowing what those fields are called and you can go in and edit them.

So somewhere in that JSON there is an object that represents a soldier, and somewhere else is an object that represents your HQ state and has your money value in it. In EW the saved game was basically a snapshot of your game state. The bad news is that a raw JSON format is not as useful for XCOM2 as it was for EW. I never fully understood the file format entirely, so there are still plenty of 'unknown' fields. It didn't require a huge number of changes compared to EW, but there are a few things in different places. The good news is the save format is very similar to EW. Warning: Long technical detail post below. I didn't get the other direction working yet. The latest (from a few weeks ago when I looked at it last) is I successfully parsed and generated a JSON file for a single sample save game. I started on an update to XCOM2, but it's been constantly pushed to the back burner due to LW2 work, unfortunately.

Xcom 2 save game editor