Xeth is stoked with the lead they were given and the neat new trick he learned, but he is hesitant to just leave Ascar here with the Atrii on... whatever their planet is named. He will respect whatever answer Roan gives but will put in his two cents that Ascar should stay with them for the remainder of the mission, in the event that the lead is not worth his freedom.
Also, Xeth is going to put the coordinates for the planet into his ship's navcomp and his R3 unit permanently, so that he can come back and practice.
Ascar says it quite plainly- the deal with the Council was that he gives you his information in order to provide a potential lead. This he has done. No condition was attached that it had to turn out to be useful; just that it was a genuine effort on his part.
As for how he is going to get around- and indeed, he plans to return to Coruscant- he gets some communications equipment out of his bag.
"I'll hitchhike," he says. "Same way I used to. If you know the right frequencies, you can contact some of those far flung traders I mentioned before. They can get me to an outlying Republican world, and I can transit home from there."