Ha. didn't see you had so many players already. You probably want a more in-depth response.

I'm currently building a special teams...specialist. So I went with FS. I like first step, change and super. Diving tackle and closing speed. I'm focusing on speed, agility, and vision. I'm going to ignore as much as possible strength, confidence and stamina. I figure if he's just a st specialist, I can get away with just those three and train up tackle. Maybe train up jumping and boost diving tackle.
As far as a traditional safety, Super Vision is king. First Step, Change Direction, Wrap up and diving tackle is where I'd go. Closing Speed is good, but costly. I'm not sure how effective it is if the play is in front of you. I would think SV FS and CD are more important since they will initially get you into a good position. I wouldn't go with shutdown coverage unless you plan to play cover 0.