Sorry, I was responding from my phone, hard to type a long one.
Yes, to both questions, i.e., you'd make use of more than one sunrise/sunset and you can easily fill 2-3 days of shooting. Especially since you've been to Moab already.
It is a relatively small park, but still has several worthy overlook points. Then it depends on the weather as well, some sunrises/sunsets might be better than others. While most photographers shoot from the outskirts above, you can also go into the canyon and explore the unusual formations from within. Then again, even if you are just passing through and have only 5 minutes to shoot, Bryce is such place that you'd end up with a decent photograph if you know where and how to look for it (as I am sure you do).
The reason for staying longer, apart from a generally good idea to immerse yourself and study the subject, is that Bryce's hoodoos in particular seems to absorb and reflect light quite differently throughout the day, depending on the nature and angle of light.