It's not so much about the camelCase, or PascalCase. Either method is fine, it's just the naming conventions need to be properly set, and everything properly adjusted.
What I did was switch all naming Conventions to Pascal Case, and went through everything. But starting from a fresh project, installing the addon, building, and then initial enabling get's the following errors in the console, and then will spam cause of a NRE when it can't find the scenes it needs in a 3D Scene for the custom gizmos.
I went through, renamed all folders to CamelCase designation, and then scanned all CS files for any res:// loading, and ensured they were properly capitalized, and then everything works just fine. I can send you a zip copy of the folder structure I did, if you want to look at the zip and see.