The standard data files can all be opened in a spreadsheet program and edited. The player's manual contains an explanation of what all the numerical values mean and what columns they go in. These are easy to work with. However, not all changes made here are applied to save game files. So yes you can create different scenarios.
Saved game files can also be edited, but in notepad. They are csv files, and some values (eg hex coordinates) need to be run through a formula to get the correct value number to use; some use 4 figure numbers to describe a status, such as organised/disorganised. This is more fiddly, but there is a thread here https://www.matrixgames.com/forums/tm.asp?m=4136832, and Steve has provided some additional detail info.
If you mean an editor program that gives you an interface that identifies all the values, and does all the maths to output a correct & functional value in the right place in the CSV file, then no. It would be excellent if someone clever such as Andrew Gailey or Jim Bello wrote such a utility for the save files, but no such luck.
"You may find that having is not so nearly pleasing a thing as wanting. It is not logical, but it is often true."
- Cdr Spock