I think I will start off with the bearing and go from there. I have seen multiple bearings fail within the first six months. It may be a quality issue or driving habits. People that park on the curb and use their right front tire to bounce off of it all of the time seem to have bearing problems. The only correlation I see between your two problems it some sort of impact. Alignment could be an issue but I would think it would wear tires like crazy instead of suspension parts. Most models recommend replacing the axle nut every time you take it off, it has sort of a plastic ring on it that is a one time use locking mechanism. As for testing ball joint and bearing, its a little harder to do by yourself, but leaving the wheel on will give you more leverage and you may notice more play. I always test such components with the wheel on and support under the lower control arm.
As for the ball joint, think of it as your fist and arm. The ball of your fist would be encased in a polyurethane or some sort of plastic, and then the metal goes around the plastic. Your arm would be the part of the ball joint with the threads. Grease is used to provide a lubrication between your fist, the ball, and the plastic. Even non-greasable joints and greased from the factory, and is the boot is in good condition, they should not lose any grease. That being said, any lubricant will lose its power sooner or later. Play in your ball joint occurs when the metal ball starts to wear into the plastic, creating more clearance between the two. Great idea to compare side to side. It requires special tools to actually measure the ball joint movement and I think its sort of a waste of time. If its loose enough to see and feel, its loose. If there is a grease zerk, it is usually on top of everything any pointing up, small metal nipple sort of thing. Most new vehicles do not have a zerk on them, and some times it is hard or impossible to find after market parts with them. Some high quality parts have lifetime warranties. I know this is something you don't want to do again, but this might entice you to buy the high quality ones.
I would probably replace the bearing for now, I know the noise can get annoying driving down the highway. The only ball joints I have ever seen break are the ones we have been recommending for years and the customer never wanted to do. I would give the ball joint until your next oil change, check it again and go from there.
Let me know if you have any more questions. Thanks.