Hello. I am having a similar problem as the original poster described. When I add a View and try to insert a field, I can see the following tabs: Post, Term, User, Site, Query, View. But my custom post type, custom fields, and custom taxonomy do not show up anywhere.
In the MB View tutorial video, the screen showed the custom post type fields at the bottom. So I am not sure why I am not getting them. My screen does not match what was shown on the tutorial.
I tried clearing the cache, but the problem persists.
I am using MB View as part of the Meta Box AIO package.
Update: I started again from scratch on a different host and everything works fine now. I am still not sure what caused the earlier problem (was it a plugin incompatibility or a server setting?) but all is well now.