Ok, lets break this down.

I'd use either redwood or cedar. They are hardy bug resistant woods.

Can't help you with a contractor. I'm a DIY guy. Check the yellow pages, and call around for quotes.

I'd ask the local garden shop what other people have purchased for a pergola.

A few suggestions: Passiflora caerulea (Blue Passionflower),
Vitus Brant, Clematis armandii, and Jasminum nudiflorum (Winter Jasmin).

We used pressure treated 10 years ago and so far so good.
As far as the contractor goes you could sign up for freecycle.org and ask there....folks do that a lot and seem to have good results.
Mine is covered in concord grape with morning glories growing on the opposite side of the grape vine. The grapevine really shades nicely , great fruit and a little color with the mg's .

I agree on using redwood or cedar if you don't want pressure treated.

For a cover, I highly recommend native coral honeysuckle vine. It is not invasive will bloom from spring on into fall, It is very attractive to hummingbirds, it is pest resisant and it is perennial. Two or three plants could cover a pergola in one season if they get sun. I have a excellent inexpensive online/mail order source for coral honeysuckle Mail Order Natives in Florida. She won't start shipping again until Sept. b/c of plant stress during the summer but her prices even with shipping cant be beat.

Penny