How to tie the optimal cordelette in this specific 7 point scenario?
Honestly I think you are over thinking this. As long as your anchor point spread out too far you shouldn't have a problem you don't really need to worry too much about transferring load because there is only one load on it. If you plan on swinging in your hammock that's a different story. On the other hand you don't have to worry about plummeting to your death either. 

You could try something like this
Using six of the anchor points that you have outlined you can easily make adjustments to the load-bearing points by adjusting three lengths. 

Test your anchor points

Start with your best anchor points. Fix a rope in place at a comfortable height for you to hold on to and do a pull-up and then bounce a little. Use your judgment to figure out the quality of the anchoring. I often mount things over people's heads and the best of field test I've come up with is to hang off an individual anchor effectively quadrupling the load it would possibly see. 

perhaps this is a more accurate representation of what you need

Once you have one or two decent anchor points the rest are just insurance.  with this setup always make sure the two best anchor points are together.