This is the apron. No foundation, concrete is paid separately, ground prep is separate. concrete delivery is separate and via conveyor truck to minimize having to move concrete around by hand is minimized. Slabs are beside a garage. As it is outside I see no reason for a vapor barrier but could be wrong.
So "forms and finishing" seemed pretty descriptive to me. They need to place outside forms on already prepped gravel base. Then guide the conveyor truck where to place concrete to get it somewhat even. Then level it out and finish. Then saw cut and remove forms.
Total with concrete is $5670 or $4.77 a sq ft. Slab is 5" 4500 PSI.
You are correct regarding the vapor barrier. No need for one on exterior concrete.
$5.00 per sf is right in line with what I would expect.
You don't mention it but I'd be wanting wire mesh or rebar.
A slab sitting on a stable base within a perimeter foundation is exposed to far fewer forces trying to split and heave it than a free standing exterior slab. As such, steel reinforcing is almost a necessity for a slab of any size. Your aprons are presumably fairly small and might be Ok but why take the chance. The cost to add a few bars or some mesh would be minimal
You are right to doubt the ability of your finisher to lift the mesh into position during the placement. It rarely work. There are any number of products available to support wire mesh and rear from simple concrete brick to concrete dobies to various metal and plastic products.