Yes possible to use an external .exe file. As long as the other .exe can write data into an external file such as a cfg or txt file or something which can then be read using Lua script into Visionaire Studio, for updating some conditions or values or whatever.
The only issue is that os.execute() will minimize VS & then launch the other .exe file. It might be worth considering having it save your game. Launch the other .exe file & then quit the VS game. Then vice versa for the other .exe after you have done with it.
There are plans for adding more features & better support to future versions of Visionaire Studio, so that it can be used for making other game genres besides: third / first person point & click adventure games & visual novels. I don't know when it will happen mind.