Of course, the Jem'Hadar might have been full of shit there, too. He listed a number of starships he knew were missing in Gamma. But starships are always missing: being out of contact with home base for six months straight is perfectly routine, and eight years isn't unheard of, either. Perhaps the Jem'Hadar never laid a finger or a phased polaron beam on those?
Verifying the fates of those ships would be beyond the means of the Federation, at least if the Jem'Hadar had their way and blockaded the wormhole. Which they failed to do, but this poor fellah wasn't to know that. The same would apply to New Bajor.
The novel Rising Son touches upon the true fate of the colony, but canonically we know zip.
Timo Saloniemi