First I would like to say that according to the yahoo site, Mesa and ALPA are not going to agree to J4J by tonight's US Airways deadline. If this deadline is for real, Mesa is out of any future expansion with US Airways.
That said, to your questions. If somehow ALPA and Mesa find a way to approve J4J, there would only be growth at Mesa. No furlough. They have a deal (only with ALPA approval) for 70 additional jets in the next few years. Unlike the US wholly owned's, who would be replacing props for jets and giving half the seats to furloughed US pilots, Mesa would only be expanding. Half of 70 is 35 times 10 pilots = 350 new Mesa pilots in the next two years or so.
Now to ugly for your friend. Without J4J and with Freedom taking all of Mesa growth, Mesa pilots are looking at a furlough soon. Everytime Freedom adds a CRJ700 (and soon a 900), Mesa is losing a 200. Because of this and the fact that so few Mesa pilots took the offer to go to Freedumb, Mesa is beginning to have an excess of pilots. Soon the Mesa Air Group will be hiring on one end (Freedumb) and Furloughing on the other (Mesa). And people wonder why Freedumb is so bad for pilots. Very soon, Mesa will go the way of is brother CCAir.
If this happens and your friend turns down a offer to go to Freedumb (which I hope for his career he does), he is going to have a long wait for a job at Mesa. If it is even still there. What a mess this has become.
I hope this helps clarify things a bit. -Bean