Megan,
Your questions suggest a general unfamiliarity with the mountain that is productive of a certain amount of uncertainty.
I'd strongly recommend that you get one of the inexpensive guides to the mountain. I think they're all good, and you will find the information valuable, and reassuring.
I've never heard of anyone seeing a mountain lion on the mountain. I'm sure they are there, but they are timid animals and rarely seen. I've seen one in 50 years of backpacking, and that was in a car.
Bears are very shy animals, except when around abundant human food. That is only down at the portal. If you see a bear anywhere else, you will be exceedingly lucky, and probably will not get a picture (because the bear will be running from you). They do not attack hikers to get your food. Forget the Bear Spray, it is only a hazard to YOU.
I think hiking poles are very useful---if you have practiced with them a considerable amount. There are some who never are able to get the hang of the coordination, and for them, they are tripping hazards.
Speaking of practice, I'm a strong advocate of practicing hiking in the dark. You develop a skill and comfort level if you do it a lot. I really got into it hiking with the Sierra Club hikes in Griffith Park in LA. And on those hikes, which has hundreds of hikers on T, W, Th from 7-9, they DO NOT ALLOW you to use lights---it destroys night vision, which you come to appreciate. I will grant that it is an acquired taste.
