Tater, glad to see a view of more photos of your project. Thanks for sharing. Nothing like family with great toys and the experience to operate same. Pass them an Iron City for me. Seriously, looking great.
Plan on LED lights where applicable. The average "Flood" lights run for 10,000 hours and draw significantly less than a normal bulb. Same for the interior. Did it to my place and it was well worth the investment. Get the "contractor Pack" at lowes or HD.
Composting toilet, good to go, as long as it is one with a good reputation. Goggle search for sure.
Insulation, what do you plan to do there. I might have a supplier who has the latest and greatest stuff to do same. Used it on my place and the materials are darn near perfect. Let me know if you are interested and I'll get you a contact number.
Keep up the great work and enjoy....