Jeep364, I don't know about swapping out appliances, but we did ask them to relocate the battery storage, which would require wiring layout changes, and they were fine with that. So they are willing to work with you. As far as insulation goes, we have been winter camping in our canvas sided, single pane, thin walled Four Wheel camper. Getting something with insulated 2" thick walls, dual pane windows, and heated plumbing and holding tanks will be such an improvement it did not occur to us to ask about more insulation.
Frank, they are saying last week of March right now. If that is correct, time from order to delivery is about 5 months.
Where did you relocate the batteries to? Generator box? I noticed they finally have some videos on their website - if you click on the Chevy build they have a pair of heated Renogy batteries in the 'normal' external AGM location.
Looking forward to updates from your new ride!