Good story. I haven't done exactly the stuff you did, but I felt your pain. Your trip also proves that a 5 year old can sleep through anything after a day of fun.
"my child's filthy foot exploring my nostrils" brought back memories. Our youngest was finally banned from sleeping with us at about age 5 as he slept like a tornado, so I too have had my child's filthy foot exploring my nostrils.
I would like to humbly point out that the answers to all of your, , , , , , dilemmas, can be found within the pages of Hammock Forums.
One I'll mention: As you mention, the sag of the hammock is critical to comfort. Once you find the "Perfect Sag" for your hammock, add a ridgeline to the hammock to "set" this sag.