Patrick Bateman, the name Dexter picks for his fake ID is the name of the main character in the cult classic novel "American Psycho" by Bret Easton Ellis.
Harry is pictured wearing the same watch (Vintage Waltham 25 Jewels) that Dexter wears in the original Dexter series. It's confirmed that Dexter inherited the watch after Harry's passing.
Christina Milian is older than Luna Lauren Velez was when she played Lt. Maria LaGuerta. Milian is supposed to be playing a much younger version of LaGuerta.