I voted Ben Johnson, primarily because of 2 reasons:
1. He's an offensive guy who has called plays and made Goff look good, which I think is harder than it might appear.
2. His personality is more energetic than Slowik, and I worry Slowik as a HC might be another Norv. (That might be entirely unfair, we'll see.)
I want an offensive guy because if we're getting a QB at #2, I don't want the offense to change every year. Stroud might be on offense #2 in his second year. If you get a defensive coach, and things work, the OC gets a HC job, and you start over with another OC. If you're planning well, you promote somebody, but that's tough to predict.
I will say, I think Ben Johnson runs the ball too much at times and gets into a run-run-run-run-run rut especially when things are not going well, and they end up punting a lot and have a tough time coming back. That's been a theme in their losses.
However, in their wins, they run the ball effectively, and have an extremely dynamic, efficient offense.
So, something to keep an eye on. But I like Ben Johnson as the #1.
If you could guarantee OC stability, I'd probably go Vrabel who I think is an exceptional coach, or one of the Ravens guys at #2 behind Johnson.