Everyone is on waivers from the start of the first game of the week until the time when Yahoo processes the waivers, or basically Wednesday A.M. If you make a claim during that time period it is a waiver claim. It doesn't matter if they're on another players team at any point, everyone goes on waivers during the weekly period described.
Rob, Patrick and Ruiner all made pickups this morning of players and they were all free agents. The difference is when they made the request which is the whole point of the waiver process. The waivers are there to help the teams that have a higher waiver priority. They have this because they drafted later in the draft process. For example, Taco's team got Cadillac even though I also tried to pick him up - he got him because of the lower waiver priority.
From Wednesday morning until the first game, whenever it occurs, all players are free agents. I assume there is an exception with players that were recently dropped as they have a two day waiver period as well. So everyone that got dropped today, whether through a free agent claim or a waiver claim is on waivers for two days. All other players are free agents and you can pick them up right now without it affecting waivers. So if you want Earl Bennett right now, he's a free agent. If you want Danny Amendola, it's a waiver claim.