My personal opinion - again, early in the draft process, and subject to change - regarding the 3 guys you have mentioned recently:
3. Gerod Holliman. He's a good ballhawk, but he's got signficant fundamental issues in tackling and run support, and questions about a chronic shoulder problem that need to be evaluated. One [anonymous] scout calls him "a mess", and I think that his interceptions overshadow some fundamental issues, so I personally wouldn't consider him before the 3rd/4th round, though I think he'll go sooner than that. It's quite possible that (if the medical issues are resolved) he can be coached up in the fundamentals and become a very good safety, but a lot would depend on the quality of his coaching and his work ethic, intelligence, and perseverence. He's an intriguing prospect, but right now I have a "buyer beware" label on him.