This sounds like a different mind frame from you: guys who are ready to go early in their first season (more or less). If that's important to you at #6, and I see why it would be, then I think guys at other positions would be a consideration. Myles Jack, Reggie Ragland, and Ezekiel Elliott may not represent pressing needs for us, but they would likely contribute well in their rookie years if we got them. I could see Ragland in particular moving into the conversation between now and the draft.
But I think you're being a little more conservative than necessary. I think the Ravens probably do value Hargreave and Stanley that high, plus Buckner. I think their board looks something like Ramsey, Bosa, Tunsil, Buckner, Stanley, and Hargreave as all worthwhile. I don't think they trade back if those guys are there, and one will be. I'm guessing Treadwell is top 10, but still just outside the top 6.