If I remember right, the 1356 has a magnesium case, it’s lighter than aluminum but can be worn through around the pump arm, causing it to spin on the shaft and not pump. As far as I know everything else you said is accurate though.
I don’t really have much experience with the 1345 but haven’t heard much good or bad about them.
I think if you get a zf5 you might look into 3.73 or 4.10 gears. My 87 has a swapped in np435 and I think 3.08 gears, 33’s and a 5.0L and it’s a dawg in the mountains here. I feel like the trans doesn’t have enough gears. I can start in 2nd as long as I’m on flat ground, I can down shift into 3rd when making right turns but need a higher gear when cruising at 45 (common speed limit in my area) but the revs are too low in 4th at 45 to make it up a hill. When cruising down the highway I don’t want to go much over 65 due to the revs (and a wobble). I would love to have another gear above 4th, then redo the axle gearing to bring all the other gears “closer together” if you know what I mean. At some point I will probably change the axle gearing to 3.55 and deal with the higher revs, maybe swap in a zf5 way down the road and up the gearing even more. But my bronco is a weekend wheeler and not my daily driver, so I would sacrifice some road manners for off-road performance. Your preferences might be different. And it might not be as bad with smaller tires.
