I don't think he has ever played free safety in his career (even HS), so he is most likely a nickel corner or bust on defense. At FSU his sophomore year he played CB opposite Xavier Rhodes (2013 1st Rd pick and current Minnesota Viking) and I only remember him losing a 1-on-1 jump ball once in his career (against Michael Floyd - 2012 1st Rd pick and current Arizona Cardinal 1000+ yd receiver) where he played the ball as perfect as possible and actually out-jumped the 6'2" Floyd to get both hands on the ball, but Floyd showed his strength and ripped it away.
Here's a link to that play and you can see his ball skills/timing and leaping ability. He lands on his head and it knocks him out, but it shows he will give all he has to make a play, and when he fails it is not for lack of effort. That play really epitomizes Reid as a defender- great instincts and ball skills and timing that can put him in the right position to succeed. But if 5'8" and 6'2" both time it right, then 6'2" wins more often than not.
You basically hit on everything else. He definitely will have a following from FSU fans who watched him, so don't be surprised to see a few attending FSU fans in the stadium hold up the "5 fingers" symbol (for his jersey #5 or nickname "G5") when he goes back for a punt. If you have 10 minutes and want to get a good idea of his on-field demeanor, instincts, and field vision check out some of his youtube highlights (he has a lot, but here are links to his
Freshman and
Sophomore years and a short one of his
Junior year at FSU). In high school he just dominated the biggest HS classification in Georgia, and was also voted Player of the Decade (for 2000-2010) by state coaches/media (including over current NFL'ers Eric Berry, Cameron Heyward, etc.).
Basically he has been very, very good at every level of competition thus far. NFL offenses will try to prey on his lack of height and top gear (like college offenses did), but he has mostly been able to win one-on-one jump balls despite this by using excellent timing and instincts. If he is plugged into a system that nullifies those weaknesses (ie. as a Nickel corner close to the line of scrimmage, minimizing the risk of jump balls vs. taller, stronger receivers) he could be excellent and a potential game-changer down the line.