Don't be too worried about whether including end notes are a risk. If the publisher or agent really likes your writing or the story, that will matter more than whether they consider the end notes to be extraneous. They would just ask you to consider not including them. Just make your submission the best you can make it and follow the submission guidelines as best you can. But if your story stand without them, then they probably aren't really necessary.
Also, be sure to keep writing! Especially if you are writing a picture book, a lot of agents will ask to see 3 or 4 mss before offering you representation. Read a lot of picture books that were published in the last 2 to 3 years to get a feel for what publishers are putting out. And don't be discouraged! It can take years for your craft to get to publishable quality. I didn't send a query for 4 or 5 years after I started focusing seriously on kidlit as a career, (though most people don't wait as long as I did). And it was another year after getting an agent that I got a book deal. You just keep writing. Find a good critique group or partner, we have boards here to help with finding critiquers, and places to post queries and parts of mss for critique. Having feedback on your work, and learning how to give it on others', is a huge part of learning your craft.