Wooderson - Your revised plan is better. I was going to warn you about the hazards of trying to permit a structure in which people will be sleeping. Let's just say... you don't want to go there unless you are prepared to double your budget. At least, that's what I'm finding here with my build.
Further, you were never going to be happy packing 5 pounds of sh*t in a 2# can. S-P-A-C-E... give yourself plenty!! My garage is slated to be 30' x 66' (more-or-less) and I think it will be tight putting three bays and a woodshop, plus the 3/4 bath. I happen to have a loft above for the "guest quarters", but I still think what will actually fit, and what I initially planned on fitting, will differ. And not insignificantly so...
Lastly, here's the guidelines I was given when planning my garage. (Mind you, I'm in Minnesota, so mechanicals and frost depth are issues that you may not need to contend with as I did.) For a bare minimum structure, $15-20 sq. ft. To upgrade (good quality overhead doors, 4" slab, interior sheating on the walls, etc), plan on $30 a sq. ft. to be closer. The more one does themself, the more one could shave off these figures, but no more than about a third if done practically ALL yourself...
How does this fit with the experience of others?