Will is easy. He was baptized Guilelmus Shakespere, but seems very plainly have signed himself "William Shakespeare" (Okay, it's more like he signed himself Will~~~ Shake~p~ar~, but you can follow the intention: there's at least a bump for every letter) and by far the most consistent spelling of his name in contemporary print is "William Shakespeare," sometimes with a hyphen: "Shake-speare."
Easy enough. It even, matches the modern spelling.
Kit is a mess. Three different spellings for the first name alone, and as for the surname... eek. However, there is hope: in both the baptismal record and in the one extant example of his signature, his name is "Christofer Marley." So that does appear to be what the man called himself, Marlowe/Marlow/Morley/Marlin/Merlin aside. (I bet it's all dialect confusion: those are all sounds that get blurred pretty heavily, depending on your accent.)
So after much consideration, he's going to be Christofer Marley in narrative, and Christopher Marlowe in citations.
What's amusing is that there's even a plot reason for that to make a certain amount of sense.
Wordcount? What's that? I'm