It looks like you've named your two tensions and so I would encourage you to try to process it in governance with any solution you find viable. It can be helpful to get specific on them.
- Validate the strategy... What does that mean to you? How is what's currently happening not meeting your need?
- Distributing Lead Link Accountabilities... What accountabilities are not happening? Do you have and idea of a system that would work?
In an anchor circle without a lead link the work typically done by the lead link can happen during a governance meeting until governance is written otherwise.
It is ok to try something that you think will solve your tension. If it isn't perfect we can at least learn from it.
Perhaps, you'd try your idea of having a large all encompassing circle then you would experience if it was too bureaucratic or not.
The tool I usually look to for distributing those accountabilities is policy. You can use a policy to grant authorities that were lead link authorities to a specific process or role.
This is the fun of the practice of Holacracy, keep at it!