Hi,
by reading the first topic, it sounds like you try to use more than one child theme !
I already have activated my other child theme
If it is the case, it’s not the way to proceed. π
1) You should have only one child-theme activated.
2) in this child, you add a folder called buddypress.
3) if you need to modify some BP templates, you copy the original from wp-content/plugins/buddypress/bp-templates/bp-legacy/buddypress/ into the child BP folder.
Example of what you should have:
wp-content/themes/XYZ theme
wp-content/themes/XYZ-child/
Let’s say you want to modify BP’s register page.
wp-content/themes/XYZ-child/buddypress/members/register.php
or you want to modify the profile header template
wp-content/themes/XYZ-child/buddypress/members/single/member-header.php
And that’s it ! The only thing you have to do is to pick the right file and add it to the child by respecting the original path who starts at: /buddypress/path/to/file.php
Inside the template file, yo can manipulate html tags and find different action hooks ( do_action( 'something' ); ). Take care to not rename or remove the existing class/ID names whithout knowing what you do.
In bp-custom.php, you can manipulate BP’s behave by adding custom functions.
In the child-theme style.css, you manipulate whatever related to your theme layout – for the entire site, including BP or other plugins.
And as all this is done via the child, anything will remain after any update of BuddyPress, your original theme, WordPress or plugins.
Reading actively the forum will bring you other answers, tips and tricks.