1- Been answered already
2-Use the CJ one or you'll have to cut holes in the YJ one and it will be more prone to leaks.
3-Yes, use the old one as a guide and as mentioned, you'll need to rivet some sheet metal over the large access holes used to get to the wiper linkages in the YJ frame.
4-It is doable but I couldn't find a YJ wiring diagram that had the same color wires as the motor I had (even though it was supposedly the same year). Instead, I pulled both wiper motors out and swapped the short arms that rotate on the shaft of the motor and attach to the wiper linkage. Shaft size and splines of the two motors are the same so once the arm was swapped I installed the CJ moptor in the YJ frame and all the YJ linkages can remain as they are.
'84 CJ-7: 4" BDS, 1" Daystar & 3/8" shackle lifts, 35" X-Terrains on steelies, Yukon 1 pc axles, YJ Tub & family roll bar, heater blower upgrade, 4.2L w/MC2100 & Team Rush, Warn 8274. Rear aussie locker, twin sticks/clocking ring waiting to go in.
The advertised position for a topless, dirty jeep girl has been filled......by my wife. Thanks to all that applied.
<------------and yes, that is her. :-D