I have no idea about which round was factory loaded to what pressures, but I do have an old Lyman reloading manual which lists data for both .25Rem and .25-35 under the same heading. (same manual has no data for the .458 Win Mag, but has a note that data will be in a newsletter around Nov 1957)
The Remington line, .25, .30, & .32 were direct competition to the Winchester 25-35, .30-30. & .32 Special. Remington also had the .35 Rem, for which, Winchester had no direct comparable answer.
There seems to be some historical irony here, as current info suggests that the Winchester rounds were loaded to higher pressures, but the Remingtons were in stronger rifles. (the bolt action, pump and semiautos of the day).
Also ironic is the only one of that Remington family to survive commercially was the .35, and for many decades, it only did so in one rifle, the Marlin lever gun!
You can easily form .25 Rem from the .30 or .32 Rem brass (if you can get it). You cannot use the .35 Rem brass to make 25 Rem the .35 case head it too big. (although a necked down .35 Rem might make an interesting wildcat).
You can turn the rims down (and cut an extractor groove) on .25-35, .30-30, or .32SPL brass, and get functional brass, but I think a bit more work will be needed. The .25Rem has the same diameter shoulder as the .25-35, but the shoulder is a bit further forward, and the case body has less taper. SO, fireforming lathe turned Winchester cases would be necessary. AND, since the Win brass is the same length overall as the Rem case, blowing the shoulder forward and reducing body taper by fireforming will likely result in cases that are shorter than .25Rem spec.
You should be able to make ammo that shoots, but they won't be "perfect", necks will be a bit short, compared to .25 Rem specs. (or at least that's what I would expect, never having done this particular conversion).
Considering the amount of labor needed to turn each WIN case (and assuming you have to pay someone with a lathe to do it), I think you might be further ahead to just pony up the cash for Rem brass in .25/.30/32 (whatever you can find), and write off the high cost as the price of keeping an obsolete round alive. After all, you aren't going to be stockpiling cases of ammo for that caliber, are you?