Elizabethan portraiture is a fascinating subject, not least because most of the sitters look like nobody on god's earth. Also, they are quite frequently identified as
a) Queen Elizabeth
or
b) Mary Queen of Scots
even when they are male. So arguing the identity of an Elizabethan portrait on the grounds it looks a bit like another portrait is not really the act of a rational being. Still...
Closeup
The Flower Boy's face in close-up. He still has the underdeveloped jawline of a pre-pubertal boy. Looks a bit thuggish, but the artist was perhaps trying to show his commanding appearance. Also, the shaven head may not have been a style choice but a side effect of medical treatment - it was often done to sick people. When Essex's father died the boy became a ward of Lord Burghley who described him to the Queen as ‘...verie curteus and modest, rather disposed to heare than to aunswer, given greatly to learning, weake & tender, but very comly & bewtifull’ (BL, Lansdowne MS 23, fol. 190r). I have a dim memory that poor health was given as a reason the boy couldn't yet travel.