The Planning Board really does not have a legal basis on which to deny the application, especially if the applicant can deal with the variances for street trees and sidewalk lighting. That said, I'm not as versed in historic preservation law, so I don't know if / how the HPC denial impacts the PB review. I assume Newark's HPC is a "regulatory" HPC, not just advisory, and therefore would likely have the power to block or delay the approval, depending on local ordinance.