Maybe a race condition ?
https://askinglot.com/what-is-race-condition-in-linux
Have you tried adding 1 or 2 seconds of delay to 2 of the 3 folders you want to launch at startup ?
About the multiple DEs, it's generally not a good idea to run thousands of them on the same install as they're mostly painful to remove properly without damages and can induce instability. There's been numerous users here with weird bugs happening because of that situation. Giving a desktop environment a try is usually best done in a virtual machine. QuickEmu does that easily and with hardware acceleration. Just my 2 cents.
And now with a GUI