BuddyPress

Use functions.php for this – not header.php.
Functions.php is loaded earlier than other theme files – but after plugins (like BP).

So if I clicked on an avatar in this thread – I would see no 40×40 px but (in a popup) 150×150 px (or other, configurable).
Am I right? If yes, I might add this to my BP Avatar Bubble […]

Yes, this can be done.
The easiest way is to create a “bridge” between them.
So in general:
1) sync all users data between sites (wp_(users|usermeta|bp_xprofile_*).
2) create a script on site 1, that after […]

Not yet, sorry.

What kind of customizations and how good the developer should be?

I will look.

In 2.3 plugin takes care of activated Friends/Messages/Activities components.

I will see how this can be improved.

The problem is in that 1 table (for roles) was not created.
To fix:
In admin area of a plugin select “Delete all tables and options”. Click save.
Deactivate the plugin on Plugins page.
Activate the plugin […]

Thanks for sharing this issue!
It will be fixed today and released today or tomorrow.

@jwolin
In next version (will be releaded soon) you will be able to use standard WP editor. Later after some testing I would like to add upload feature, but it’s pretty tricky to make it secure so I can’t promise anything.

How have you created the task twice? It’s impossible – as each time you are creating different tasks but with the same name.

Fixed in earlier version. Please upgrade.

Thanks
The code rewrite is almost done. In general small fixed and new featured will be in every new release.
I will maintain actively this plugin.

Could you please give me a screenshot of a problem?

Thanks for saying this.
Closing the topic.