They are a source of food for the next step in the food chain. You risk disturbing the entire ecosystem by eliminating mosquitos. Maybe some other insect will take their place, but the you risk eliminating the species as well because to many are eat.

It’s insanely complicated, and you can’t think in terms of benign or not. All animals are benign, they’re just animal filling out their niche in nature.

I don't think we can know with absolutely certainty, and driving a species (or many) to extinction is irreversible with our current technology, so we should think real hard before choosing to wipe a species out.

You are missing the point. Gene drive can do this to any species.

Now the clouds part. Mosquitoes are just the first guinea pigs to see if this Gene Drive works as desired or not, am I right?

We do not understand well enough to even believe we can properly assess that question, let alone express reputable confidence.