And if that goes well, we are going to start building them and trying to sell them.

The necks will probably me Moses necks, and possibly some Warmoth necks.

Now, body wood.

We need something dependable, and that sounds good. We are going to try to build a 6 string fretted as our first project.

What would be some good woods for a 6'er?

"Dependable, that sounds good"

Well, alder will not fail you. Neither will walnut or cherry, ash or elm. Even birch or poplar will do a nice job.

Actually, species is not the issue here, except to some extent regarding looks.
The quality of the actual plank is of more bearing to both ease of work and tone.

Mahogany