Re: Theme template files not being loaded
bp-default child themes usually render something like below in Appearance > Themes
The template files are located in /themes/MyChildTheme. The stylesheet files are located in /themes/MyChildTheme. MyChildTheme uses templates from BuddyPress Default. Changes made to the templates will affect both themes.
Tags: buddypress, multiple columns, fixed width, group blog
Creating BuddyPress Child Themes – https://codex.buddypress.org/how-to-guides/building-a-buddypress-child-theme/
and remember to add “buddypress” to Tags in style.css of custom child theme