FYI: The custom user fields' issue is also a hinderance when installing a custom module via Module Loader.
The Module Loader stalls at Rebuilding Layouts
The Unknown column 'users_cstm.sales_sub_group_c is again due to
being rebuilt and having
'custom_fields' => false
I can get around it by changing the cache file by hand and repeating the QRR which then prompts me to build the tables for the new module, which I execute. I then have to manually add the newly installed module to the Displayed Modules.
A bit of a pain, too painful/risky for production, but it works.