[@mention:508243854762339714] Wow, that's a lot to unpack. I'm going to follow your bullet points in a quick-hit response and Bernard-Marie or others may have their own thoughts.
Bullet #1 - Got it
Bullet #2 - This sounds like it may be a bad structure. Circle 2's accountabilities do not need to *specifically* mention the accountabilities of Circle 4, but there should be an alignment as you move through the nested circles of the structure. Circle 4 sounds like it may have been out of place. An issue here is whether Circle 2 had the authority to create Circle 4 (via it's sub-circle, Circle 3).
Bullet #3 - This sounds like a circle in need of some coaching (or realignment or disbandment), but those issues are beyond the scope of this thread.
Bullet #4 - This sounds like a circle in need of some coaching (or realignment or disbandment), but those issues are beyond the scope of this thread.
Bullet #5 - Got it. S/he may also need some coaching.
Bullet #6 - This sounds like a positive step. Circle 2's LL should have a tension about this and the strategy meetings strike me as an OK approach.
Bullet #7 - Here's where we get to the crux of this particular thread. It sounds to me like Circle 2's lead link's actions were far beyond the scope of his/her authority. The lead link can't restructure his/her circle alone; that is a decision of the circle that must be made through the governance process. Have you seen the warning notice when a non-secretary tries to open a meeting in GlassFrog? That's a good, simple clue about the limits on authority of circle members (including the lead link) to change the circle's governance on their own.
So, with regard to Bullet #7, what to do? [@mention:449833773917801859] is a far better guide here than I am, but my reaction would have to take into account who the people involved are and how long ago this happened. At the least, it seems that several members of the GCC, who all seemed willing to let this happen, need coaching/instruction on the scope of LL authority. If it was recent and if it is feasible, you could consider asking the GCC secretary/Circle 2 secretary to strike the invalid governance (see Constitution 3.4.4). In any event, I would emphasize how important it is to all circle members that the lead link not overstep his/her authority. Some circle members may not be comfortable saying something to the lead link due to power dynamics, and behavior like this can breed resentment and undermine your Holacracy implementation.
So those are my quick thoughts -- curious to hear from others, and good luck!