With the greatest respect for what you have been able to accomplish with having developed thousands of scripts with dozens in daily use, of various types, I would like to offer some thoughts having worked through a variety of organizations and software development projects large and small, and having done lots of scripting myself on various platforms:
This feels to me like it probably will become a much more complicated, time-consuming, resource-intensive, and demanding project than I think you may perhaps realize and be preparing for.
To emphasize ShaneStanley’s point, if you’re mission-critical with outside scripts that can only run with CS6 and your organization is planning to roll out a major upgrade to Catalina, may want to anticipate a showstopping problem that will involve re-planning the entire upgrade. Timetables -can- be changed in the face of new information.
You’ll need to get buy in -and involvement- with your top planners and decision makers, as well as your end-users.
Your few users who run the majority of your scripts will probably be heavily impacted by the process of upgrading to Catalina, and by migrating the scripts to the new platform.
JMichalTX’s points (2) 6. and 7. are -very- good advice.
It’s genuinely hard to know what users are experiencing from a verbal description, even if you are all close together in time and space.
Expect the unexpected. Expect things you can’t anticipate to eat up a lot more time than you can plan for.
Develop some kind of a system to record problems. It doesn’t have to be a full defect tracking system, but you will need at least a spreadsheet or some kind of a document to track input from users, dates, affected scripts, what machines have which versions of what scripts and when they were deployed, etc.
Aparently there are some apps in Catalina that have serious bugs involving their scripting interfaces.
Do you have any documentation? Test plans and procedures? Measurable objectives for what constitutes success? Timelines with identified critical paths? Thse are all basic elements for a successfull rollout.
This might be a good time to think at least a little about your entire scripting architecture, and consider how your choices of scripting languages and design will play out in the future.
If you don’t already have an Apple Developer account that would be a very good thing to invest in.
Lastly, consider bringing in some help. This could greatly increase your chances of success in an accelerated schedule. You’re wearing a lot of hats here - requirements, design, development, debugging, testing, integration, systems, user support, planing, project management. Someone with solid experience in this area could help take a lot of weight off of your shoulders, and this project might not even be feasible for one person to do, even if there were a more realistic schedule.