Hello there, Jules! Welcome to planDisney. We are so glad you stopped by with your planning question!
You are in the final countdown, and your Disneyland visit is almost here! I am so excited for you, and it sounds like you've had an addition to your party. As far as entering the park, your added Guest will have no problem entering the park when you do as long as they have a
valid ticket and theme park reservation. The only way to add them to your party in advance is to continue to check the availability of making a new reservation or to see if you can modify your dining reservation for
Plaza Inn to add an extra person. If there is no availability, I recommend going to Plaza Inn early and asking if there is room to add one person to your reservation. It's not guaranteed, but it's definitely worth it to inquire.
Going back to entering the park, you do have an earlier dining reservation, but you will enter with all the other Guests arriving for rope drop. Gates will open and allow Guests to enter before the
official park opening time. When I am planning to rope drop, I like to try to be at the gates about a half hour before the park opens.
Jules, I hope you all have a wonderful time at Disneyland and enjoy your Plaza Inn reservation. I am sending pixie dust and hoping you can add your plus one to your breakfast because the best way to start the day is with Mickey waffles!
Carrie