When I was doing my parts collection for my 47RE, (that I never finished) either way, I used a couple places.
Goerend for the bulk of the stuff, VB, TC, some Shafts, and their rebuild kit, but I called them and we worked it out over the phone not the website. They ask about your use and the skill level. They really don't like selling to the general public, not that I consider you that by any means. But like in my case the VB and TC both had core charges, they only got my TC back because of how slow my rebuild went.
I messed up a seal and it was a hard to find part so I just got a TransGo kit, it was a little more $ but got a bunch of spare stuff.
Snap rings and the sort were RockAuto but were Mopar from what I recall. There was one that is recommended, maybe on the one OD drum, it should be replaced.
Hard parts like the one way sprag, sun gears, if the sprag race is loose in the case that's a show stopper and needs special work.
Even the pump, mine seemed fine well within the spec, but project creep sinks in and some folks say always replace the pump with an OEM unit, which I don't think I could find back then anyway so was not an option. I see a few years later now folks make the pump gears for Mega $$$, but it's probably not much when you know the time and effort to make that part is. And it's a very small market.
I still have the special made OD spring compressor, and the cut off output shaft, I got them from Cascade, they are probably out of business by now, some of that is needed but adds to the price, I could tool share that with you if the time comes and you pull the trigger.
It was nice having not to rig up a deal for the OD set up, the tool they made was nice to have.
Maybe hook up with Cerb at their shop and do a 48RE build for the ages and document for a refresh of the TDR stuff.
Good luck on you rig.