TL;DR the python code. What happens in you just use a batch scripts and call both simultaneously?
Again, maybe some explanation of what you are trying to do, how things are connected, etc.. would help get to a solution. Do both the scripts use the same bus? (i.e. are they fighting for resources of GPIB/RS232 at teh same time?) How are you physically connected to both? Why not just do both calls in python if you are only using LabVIEW for a GUI?
They use different buses. One is connected by LAN and the other by RS232. I tried your third suggestion but was instructed to keep separate since they might not have to run together every time.