EDIT
Walker450 You must have posted just as I began composing this masterpiece of advice. It reads like I didn't read your last post- because I didn't. :laughing:
I think it is admirable to want to build debt free and you should be able to do that given your family & neighbor support system and your own personal knowledge. I would count on the support system for knowledge and guidance more than the labor. If you can get some helping hands on a few things that are hard to do alone, that's really all you need. I am assuming you are reasonably young, highly motivated but patient, have a wife that is 100% on-board, and you are physically fit. :laughing:
There are some things I wouldn't do myself, like slabs and foundations. I wouldn't think of doing drywall or other overhead sheet work alone without a panel hoist. Set up a chop/mitre saw with long extensions that makes accurate cuts easy. Having the right tools for working alone can make most jobs a lot easier.
If building permit restrictions won't let you do what you want, I'm sure there are house designs that lend themselves to building in stages that aren't wasteful. I would avoid do overs as much as possible. For not much more square footage than your garage, you could build the "core" of a larger house that is a complete stand-alone but small home. Your family would be happier with that than the garage. Get that much under your belt, take a breather and then put an addition on. The key is to begin with a house design and roof layout that lends itself to that approach. It may not be your dream design, but it is the one that will get you where you want to be most efficiently.
For example, a 1-1/2 or 2-story core space that will later have 1-story extensions allows you to build the roof correctly and permanently. A core space house could eventually have a bedroom/master suite addition on one end, and a family room & garage on the other. The supply and waste plumbing, heating & cooling, and electrical needs to be planned for the eventual full size of course.
Tyvek house wrap will last a year where the extensions tie into the core. You don't necessarily need to put exterior siding on then take it off. Even if you must put siding on, then painted T-111 is not expensive in the overall scheme of things and is easy to cover or remove later.
It's a long job no doubt. You should approach it as such, be willing to take some time away from it but set yourself firm goals--or become one of Eddie's customers.

Plenty of research time needs to be included in the work plan. You will get sick of going to the lumber yard, etc. It can also be a source of immense self satisfaction. Many don't get the chance these days to do things for ourselves and by ourselves.
The idea of first building a shed or something similar is good. It sure helps to have a place to store tools and materials secure and out of the weather. It will always be useful to have a shed for tractor parking if nothing else. You know it won't go to waste.