Character? I guess chipped paint, scratches, and rusty bridge parts add character too? I don't call that character, I call it a bargining point to get a lower price.
Some wear on the frets is normal, thats whats going to happen if a guitar gets played, as long as you are not getting alot of buzzing, random bad intonation or dead spots, the frets are probaly OK, you can have a repairman do whats usaully called a Level&Polish and that will take care of normal wear until they wear down so much they need replaced. The A string problem? Who knows, I'd have to see it& hear it . You hear more of the Wah effect on the bridge P/U, because it has has less mid-range than the neckP/U, the WAH is a mid boost, plug into your amp and roll the mid control from 0-10-0-10, a couple of times, thats what the wah does basically......cheers