First, who has a fleet of ha'taks like that? I can only think of the Lucian Alliance, but I don't see any motive for them to attack a research station. (Going down the "oh, there was that one last System Lord we happened to miss" route would be really lame.)

Second, I know the Asgard technology was installed on the Odyssey and not the Daedalus, but unless this is occurring only shortly after Unending, one would think that at least their weapons systems would have been upgraded. The Asgard have beams that can take out an Ori ship in two or three hits, a few ha'taks should not have caused them a problem.

Third, each Stargate has a unique point of origin, which is the only symbol that differs between Stargates (within each galaxy). The gate at Icarus should not have had Earth's point of origin as a symbol, and if it did, it would have been eminently obvious, and it would not have taken six months and a genius drop-out video gamer to realize it.

The Ancient communication devices were a good touch, though.