Originally Posted by Zoom2X
OK, some powders burn faster than others and a heavier bullet needs a faster burn, right?
No. Other way around. The heavier bullet goes slower, giving a slow powder more time burn, which slow powder needs. It is light bullets and slow powder that don't play nicely together, often resulting in a lot of unburned and otherwise wasted powder. The heavy bullet can still be propelled by a fast powder, though. It just can't be made to go as fast as a slow powder can make it go. In principle this is because the slow powder peaks when the bullet is further down the bore, making more space behind it, and thus you can use more of the slow powder without exceeding safe pressure.
I'm going to agree with the recommendation for 231. You'll find .231 can be used for target loads up to full standard velocity and muzzle energy loads in all the cartridges you named. I prefer others in specific applications, but you need a powder fine enough and bulky enough to accurately meter the 1 to 1.5 grain loads in the diminutive .25 Auto cases. The several flake powders mentioned will be harder to keep consistent in such tiny charges. Indeed, I expect you'll find it difficult for most measures to give you charges that small at all. You may wind up taking a .22 rimfire case, soldering a wire to the rim as a handle, then filing its length down until if forms a scoop the right size for the small charges (assuming you don't want to weigh each one).