From what I read, knowledge on the Anapheles gambiae is quite good but I don't think elimating the species will eliminate malaria. there is other vector for the parasite. The extinction migth have an impact on the enviroment because you remove a prey for predator suc as bird and fish. It is hard to determine how many eggs are eaten before it hatches and how many mosquito larvae reach sexual maturity in the wild.
What does HEG does exacly, your explanation was not to clear.
I also hear that they trying to create a genetically modified anapheles. the modified mosquito would have a less hostipal "enviroment" for the malaria protozoan.
Control will defenitely be effecient, Florida and lousiana does not have malaria problem anymore.