And go to Idlib with the Nusra-types? F that. Don’t they have the option of just retreating into Jordan?

Actually, one of the bullet points of the Russian deal was that the rebels couldn't be relocated to Idlib, which is what rebel groups were trying to negotiate, I suppose.

As for Jordan, they're looking towards normalizing their relations with the Syrian gov and get it over with this rebel thing as soon as possible, so it's very unlikely that they would allow them to cross into their country.

Jordan doesn't want them there. They closed the Syrian border even for civilian traffic to prevent refugees from entering nevermind fighters or ex-fighters and have tanks positioned opposite it.