I’m not sure I understand your first question. For me, the first state has a copy state actuator, copying any other state. Then, is the case of animations, that other state has a delay sensor connecting to an actuator that copies the first state. Maybe that helps.
For the second question; YES. I started using the state system for pretty much all of my characters actions. It does three things, avoids clutter in your logic bricks, by sorting them well, avoids using needless properties for obscure tasks, and most of all, it keeps your animations from getting confused and either playing simultainiously, or not playing. It does the last thing by deactivating every sensor, controller, and actuator not linked to the current state, so if you only have one animation per state, you’re fine. As soon as I’m able, I will post a blend file that gives examples.