That front axle should be about 60"ish wide between wheel mounting surfaces. You'd definately have to outboard front spring hangers on the frame in order to run the axle full width. However, I think if you narrow the long side about 4" (it's been a while since I researched), you can reweld the driver's side perch and bolt it in without outboarding.. again, I'm not positive.
If you were able to narrow the axle to around 56" wide and run it, you could then seek out a 58" Scout rear. Add a 1" spacer to the front axle to even them out (or not) and it would'nt be obnoxiously wide. I run a pair of 58" wide D44s under my CJ5 and like the added stability off camber.
Double check to make sure the rear is a centered D44. I'm not sure which Waggies had centered rear axles or offset (Qtrac) rear axles. Also, some Waggies had a M20 rear axle.. although the Waggie used factory 1 piece shafts. Again, I'm not sure which years.. just some info to look into.
A good running AMC 360 for $300 is a pretty good deal.
A $400 D300 is on the expensive side.. $200 is more like it. Maybe $250 with a twin stick.
A 727 in a CJ can cause fitment issues with the front driveshaft. If you run it with a D300, you'll need at least 4" of lift to have the front shaft clear the transmission. Not sure if clocking the Tcase helps or not.