Yep, I made a few typos that broke the setup process for more than 3 doors. I pushed another update that should hopefully fix that now. @wolfewl - let me know if that works for you.
I would also recommend checking out the Community Installer SmartApp. Once you have that running, you can open it, choose MyQ Lite, and just hit a single “update” button to get the latest App/Handler code installed in your environment.
As far as deleting goes, yes, there is a known issue with SmartApps where you cannot automatically delete devices that are used in routines and things like ActionTiles. You have to manually go in and force-delete the doors first, then you can delete the SmartApp.