I am all for limited vaccinations for adult dogs.
But, with puppies... I would NOT skimp, on anything. Parvo especially. The shots they are getting now are setting up a defense for the rest of their lives, and saving some money is not worth endangering the puppies lives.
Heartworm preventative is extremely important, especially in such a high-risk area. I have heard nothing positive about the annual heartworm shots that have been tested in the past. Go for the preventative, and charge their new owners a little extra, if you need to.