Looks like you would definitely benefit from someone familiar with quite a few interfaces and someone that's able to bridge the gap between the sales and marketing teams. I couldn't tell from the description, but does the person have to be in San Fransisco? What we've seen is there is a TON OF talent in not-so urban areas, and usually at a more affordable price. Or are you open to a remote worker?
Also, when you get to the interview process, you may find these questions to ask helpful, especially if you're not a Marketo Master yourself: How to Identify Your Next Rockstar Marketing Hire? 5 Interview Questions to Ask