I'm glad you described your market a bit.

I have not seen a retainer model work in this space, but that's not saying you can't succeed with it.

YOU are the expert, so I would not leave it to clients to choose what they want. If you do, you'll get clients who say, "Yeah, I hired them to make me a page; it looked nice but didn't work"--and who is responsible for that?

I have seen both arguments when it comes to the question of displaying pricing. I think you should show it. That's a qualifier for visitors, and you do not want to waste your time and energy on people who cannot afford your help.

So my recommendation is to list your services with pricing, but make sure you have a lead capture system to pre-qualify. Then talk live to fully qualify and give your expert recommendations.

I kind of like #4, but there is so little opportunity cost in you being able to offer all the other kinds of content...I would only take this approach if you are committed, really want to specialize, and get known for these kinds of pages.