The OP doesn't make it clear ...... Does a teammate/s of the BC 'join/bind onto her' Before or After the BC is shoved back across the Goal line?
If After, then you merely have a 'held hug ' until teammates arrive, & their late joining now signals a properly constructed/formed maul.
But if it was before then everyone agrees a maul can't be formed in goal - it is only formed within the FoP. But, Conceptually can the shoving of a BC (and his/her 'bound on' teammates) "begin"a maul the very instant they shove the 'hug' beyond the goal line back into the FoP, is the beginning merely dependant on the crossing of a line ??
. A maul therefore consists, when it begins, of at least three players, all on their feet; the ball carrier and one player from each team. All the players involved must be caught in or bound to the maul and must be on their feet and moving towards a goal line.
. All these conditions now exist at the line crossing.
As an aside,
1) Pegleg says that "dangerous collapse" is being considered by him, dangerous collapse of what exactly ???? Yes it certainly appears to be a maul but he's already said it isn't, so what dangerous collapse is he assessing ?
2) In the OP the 'zombiemaul' quickly ends, but what would happen if it didn't?? and it continuously rumbles/driven say 10/12/15/20! Metres upfield , would players be expected to observe 'maul' offside lines as it does? .... I'd say that everyone would expect this to be now considered as a maul, and that viewing is 'crystalised' where exactly ??? 10m,8,5,3,1m from goal line ????????