Migratory steelhead will have a twofold instinct when it comes to feeding:
1) The feeding habits they acquired as parr/smolt/fry
2) The feeding habits they acquired out in the lake
Primarily, the first will dominate in rivers/creeks. Hence, flies, jigs, roe bags, insects are best.
Secondarily, their predatory instincts can be triggered by flashy lures.
Would a live minnow work? Probably, in some situations, but I think the other options will almost always trump the use of minnows for steelhead in creeks.
If I was fishing for landlocked rainbows, it would be a different story, and flashy lures and/or live minnows would be excellent choices.