I see you are likely a student, and have no real world experience...
From someone who spent 20 years designing molds...
I would add an approximate overall height for the core. (for ordering material)
Need a couple dimensions locating the part in the mold.
Where is the gate? (where the material enters the mold)
I would also use core pins for the cored out areas from the cavity side. This makes machine much easier.
Probably need some water lines for cooling.
Tolerances on the side-action need to be called out tighter... Like a slip fit.
How is that side action activated? Cam pin?
Need some screws to hold them in to the "a" and "b" plates.