1. Do I need to hang my food in a bear bag?
Yes, we don't want to habituate any animals to feeding on our food. As other said, raccoons and rodents are problems too. Many people won't cook in camp to keep the food smells at a minimum-- they cook on the way instead.
2. Do I need to be concerned about any non-human predators?
Keep the food under control as above. Make some noise so you don't surprise a bear, especially one with cubs. Attacks are rare-- you're in more danger driving to the trailhead.
3. Is going alone a bad idea?
I usually go alone. It is my re-creation and I like the peace and solitude. I like hiking at my pace, stopping when and where it suits me.
Always let someone know where you are going and have a deadline. I leave a copy of the trail I'm going to and a "call by dark" deadline with my wife or adult kids. I don't do any technical stuff when alone--- falls are more a problem than anything. I always use maps and compass and carry the essentials.
It can be freaky to get out of your shelter at 3 AM to pee under a full moon. Your head just doesn't turn far enough around