What years is the CJ in the junkyard? If it's 82-86 it has the wide trac axles.
I would keep the YJ tub (it's galvinized) and swap out everything else. The older Dana 30 front and AMC 20 rear, are a lot strong then the axles you have now. FYI the Dana 300 transfer case started in 1980 and went until 86' 79 and older had the Dana 20 unless it was a auto trans.
80' CJ7, 360 Howell Injected, 3" single exhaust, NP435 4spd, Dana 300 AA clocking ring, Currie twin stick, Tera-Low 4 -1 kit, Dana 44 front, cut 10" wider to 63", 4.10 gears, ARB, Yukon axles and Super H/D u-joints, Currie Dana 44 rear, cut wider to 60 1/2", 4.10 gears, ARB 35 spline, Currie 35 spline axle shafts, 2 1/2" x 11" Ford drum brakes, CJ-SOA conversion, Tom Woods F & R drive shafts, Warn 9500i winch, 6 point cage, Homemade F&R bumpers and tire carrier, 1" body, Pro Comp supension Kit, 12.5x35x15 BFG's, 15x10 OMF beadlocks, Body armor, OBA.