Yes, I've been doing this for years, you just have to make /app/data friendly enough for apps to find what they need. This generally involves setting a few env variables:
HOME
PATH (including NODE_PATH avoiding npm i -g)
LD_LIBRARY_PATH (less common)
other app specific ENVs
All of these changes do not affect the running app since it's already running with its own ENVs.
So these are great for additional services.
Nice work @djxx