Okay, I'll bite....
What the LBS is telling you is true- it's gonna cost you more in the long run to do the conversion (especially if using LBS labor).
I don't think the flat bar controls would fit on the tops of the drop bars. Road brake levers work with road brakes, not with mtn brakes. There are drop bar bikes that have disc brakes, but those are road specific. Road shifters won't play nice with mtb drive train components....
But the clip on aero bars will work- there are a couple of regular BF members that have them mounted- one put them on a (7.3?) FX and the other on a cyclocross, but not sure if anyone has done so to a bike with a suspended fork.