3 site network going live

but I can live with http://example.org/wp/sub1/ and http://example.org/wp/sub2/ if this too complicated.

Good, cause with WordPress installed in /wp/, that’s what’s easiest.

The only way to do what you want is:

1) Move WP to / instead of /wp/

2) Remove Multisite, Give WP it’s own directory (yes, you have to do this BEFORE Multisiting), and then re-do multisite.

Nope. The paths have got to match or WP gets angry.

Depends what you want to do. I presented you with two options.

Moving WP? See http://codex.wordpress.org/Moving_WordPress#Moving_WordPress_Multisite

Giving WP it’s own folder? This:

Remove Multisite, Give WP it’s own directory (yes, you have to do this BEFORE Multisiting), and then re-do multisite.and then re-do multisite.