I figured out the cause of one of the problems while waiting for my daughter’s Christmas concert to start: I said above that VASL.build.module.ColorChanger doesn’t exist in VASL, but that’s not right. It does exist, but it’s in the same file as ASLChatter. That’s unexpected and contrary to good practice, which is why I didn’t spot it—ColorChanger should be in its own file. Anyway, the problem there is a bug in VASL, so I’m kicking that over to them: NPE in VASL.build.module.ColorChanger · Issue #1055 · vasl-developers/vasl · GitHub
Your most recent error log and the results from the diagnostic program show that you’re no longer having the SSL certificate error. What ISP are you using for connecting to the internet? (I suspect this issue has something do to with a particular ISP.)
I’m not sure yet how the oba-flowchart extension can be calling a method removed in Vassal 3.6 without your seeing an error dialog telling you that immediately when you open VASL.