Hello, I'm from Maryland too!
Welcome to the world of Canvas. My background is K-12, and I recently helped my district launch Canvas, but I am currently working in HigherEd supporting faculty and staff with Canvas. Coming from a K-12 background to HigherEd has taught me a lot. I have experience using Canvas as a teacher, trainer, and now an Admin and each perspective has given me a better understanding of how Canvas works.
First, if you haven't done so and are able to, I recommend taking the Canvas Educator/Technical Admin training/certification. The educator one is good for getting a basic foundation on how to use Canvas as an educator. The Technical Admin is good if you have some level of Admin access to Canvas and helps you plan out district-wide how you want to implement Canvas in your institution.
What lessons did you learn in the first year of using Canvas? - To make life easier for your teachers, have a really thorough template/blueprint that is easy for them to take and go. This will help lessen the need for teachers to learn EVERYTHING about Canvas. Once the teachers have an understanding of how to edit the content then they can take the next step by creating their own content in a course. Make sure you are not trying to have the teachers learn everything all at once. I would tell my teachers to have a home page and do a low stakes assignment to get a feel of how it works and how it works for their students. Then, try a different kind of assignment or integrate one LTI, and so on.
What would you have changed and done differently so that teachers, students, and parents were better informed? - My K-12 district came from using Google Classroom to Canvas, which was a big learning curve. It helped to use terminology from Google Classroom for teachers to understand how Canvas works. Having a transitioning user cheat sheet would have helped.
What caused confusion that we could avoid? - The ability to create any assignment and page can be accessed anywhere (modules, assignments, quizzes, discussions). A lot of teachers didn't understand the difference between the assignments, quizzes, and discussions page from the modules page. Explaining that each thing has its own house and you can organize it differently within modules and that "deleting" it in modules doesn't delete it; it removes it only in the module page.
These are the things that stood out to me the most, but I am more than happy to discuss more. I hope this helps.