Death Eaters: Still unanswered from GOF

[i_am_lord_voldemort00]

No: HPFGUIDX 62794

 JKR  does not mention things randomly,  passing comments become
crucial pieces of info later on. At the end of GOF, Voldemort speaks of
specific Death Eaters.  Those were Pettigrew, Malfoy, Crabbe, Goyle,
Avery, Nott and MacNair (present)  Rodolphus and Bellatrix Lestrange
(in Azkaban).  

Voldemort also mentions his most faithful servant who was at Hogwarts
(Crouch Minor), one too cowardly to return, and one he has lost forever.
Who are these Death Eaters. (If Snape is one of those two Death Eaters
and yet capable of spying on Voldemort for the Order of the Phoenix,
there is a leak in Voldemorts circle.)