Don't sell the other extensions -- keep the .com, .net, and .org as a block (you could probably let the .info and .biz drop). You might be best to renew those .info and .biz for another year. Don't sell those two, it will dilute your personal ability to brand if you develop the site yourself. Holding the main tlds as a block will make your name have much more value in this case.
Since you own all the domains iterations, any issues with past owner really don't matter anymore. I was more concerned that a questionable character owned the .com version of it. The .net would thus have a lot less value. Anyway... uploadwire.com is a solid name (has flexible uses, memorable enough, etc) and since you own the the major tlds, you have a reasonably protectable brand. $100 was a fair price. I think other resellers would be willing to pay $100, possibly up to $250 for your block.