Update on what I found -- and did.
Referencing the parts diagrams I posted above and this short-hand:
front gear case = FGC
front spindles and final drive gears = FSFDG
FGC #25 was bad - 2 balls gone and the metal bracket holding the balls together was broken.
I removed most of FSFDG and most of FGC (but left #14 attached). I washed out all the parts with diesel, wiped clean, and blew-out with compressed air. I strongly considered replacing FSFDG #6 and #13 (the bearings that hold the axle), but they seemed to be running smooth enough, so I re-used them. I did take them completely out and washed thoroughly. I had the JD dealer look. He thought they were OK.
I replaced FGC #10, 12, 22, 23, 25 and the gasket (#10) on FSFDG. #25 was the destroyed part, and so I figured it best to replace most of what was in-line with it, especially the #10 bearing at the top. #12 is also where the pinion shaft (#13) rides. #22 and #23 are the oil sleeve and seal, so figured it was a good time to do those.
Bad #25 had to be pulled out. This --
3-Jaw Pilot Bearing Puller -- would have been handy, but I got it out another way. The new bearing dropped in with hand pressure. #6 fortunately pulled out with hand/light screwdriver pressure. With it out, I could use that puller to get #7 and #10 out. Later I learned #10 could be pulled out from below, but that means #14 has to be unbolted to get that gear out of the way. I pulled #10 up and out of #14. It took time, and the puller had to be fitted (ground) to work. I bought a set of cheap snap-ring pliers to get #8 out. Again -- I washed out #14 and all the components.
I used a chisel to cut off #23 (careful not to go too far) and a hacksaw to cut out # 22. Those seals fit very, very tight, and are way more difficult to remove than I expected.
I assembled by putting together FSFDG #3 to #12 as one unit (I did not take #4 and #5 apart). Then I put all the parts back into FGC #14 (12, 10, 9, 8, 7, 6). #5 stayed intact on #1. I hand pressed #25 into #26, and then #13 into #25. I took that assembly (#26 with 25 and 13) over to #14 and put it up into #14. I pushed it up into place as far as could, nudging the gear (#11) into proper position, and getting #13 to start into #10. I held all that in place and bolted on #1. The only part that concerned me was that I could not tell how engaged #13 was with #10. I was at the mercy of bolting those two assemblies together to "press #13 into #10". Assuming all the spacing is good, they should have joined properly.
Finally, I put the FSFDG #10 gasket on, and attached the assembly (#3 to #12) to FGC #26.
I added oil via both covers (FSFDG #7) and the main fill plug (which is on that other diagram I have not referenced here). Just using the main fill plug would take a long time and it would be easy to under-fill.
So far it seems to work. Time will tell. There was some wear on those meshing gears (#13 and #11), but hopefully they'll last me another 1000 hours or more. Now that I know the procedure, I may open up the other side and replace those leaking sleeve/seals.
Notes:
-- that pilot bearing puller from HF is ok. It can do the job, but go easy on it. Also I had to grind it down a bit to fit inside the bearing I was pulling. I comes with the ability to get inside 3/4" ID, but I needed about 5/8". It's soft metal - so go easy, and if you use if a few times, plan on taking advantage of the "lifetime warranty". It did the job and for $17, hard to complain.