Is this a foster fitting on the end of adaptor? Can I fill a marauder with it?
Yes, a Marauder will fit on the Foster QD on this item.
Where can I get a longer hose
Take a look at AV-00035 [Air Venturi Microbore Hose, DN2,...]
Will this work on the discovery?
Will this fit the Crosman Rogue without additional adapters?
will this work on the airforce condor with the spin-loc tank
Yes it will work. The female quick disconnect will attach directly to the male fitting on the spin loc tank.