The use of a waitlist is the primary method that private schools use to ensure that enrollment targets are met. Once offers go out, the students typically have one month to decide whether or not they will accept. To offset this, most schools will admit more students than they have seats for. This is known as yield.
So if the yield is lower than expected, then the admissions office will start going to the waitlist. The waitlist is not a simple ranked order list. Instead it will be broken down into different buckets: gender, financial aid, etc. So after the yield is assessed, the school will then try and ensure an equal balance of all priority categories. Then they will pull kids from the waitlist that fit the needed criteria. It highly depends on what the yield will be this year at Newark Academy.
In recent years, very few of the private BS have taken kids off the waitlist. So while its okay to maintain hope, move onto other schools that have accepted your child. Best of luck.