No matter what the question here I think you will get differing opinions . This question will be no different I think.
Anyway, my ideal
Short Yardage back I want high strength , then elusiveness, then the secondary attributes of Ath and tech.
For 3rd down back I figure it means he will have to be able to catch passes often enough so I want my 3rd down back to be a good runner(just in case) with the best pass receiving attributes of my rb's(speed, elusiveness, tech, then ath. )
Slot receiver I never set. I let the A.I. do that. And I have run some incredible passing offenses so that has worked fine.
Best of luck.