An unknown member of the Order?

[mongo62aa]

No: HPFGUIDX 73858

Michele Childs:

Let us see who is in the Order in the first place, shall we?  We 
have 1-Dumbledore, 2-Moody, 3-Tonks, 4-Mundungus, 5-Snape 6-Molly 
Weasley, 7-Arthur Weasley 8-Lupin, 9-Sirius Black, 10-Hagrid, 11-
Arabella Figg (a Squib).  Then who are we missing?  I must have 
missed one or two at least!  There must be several unknowns or are 
we just given an estimate?  

snosageau:

12) Bill  13) Charlie (working o/seas) 14) Kingsley  15) McGonnagal?

Bill:

16) Elphias Doge 17) Dedalus Diggle 18) Emmeline Vance 19) Sturgis 
Podmore 20) Hestia Jones

In addition, somebody was on a broomstick high above 4 Privet Drive 
to give the signal.