Thats the route i use post match. there is a 21.59 & 22.12 from NP. As you say, pick up the Victoria from Tottenham Hale. I go this way as it a bit more civilised than WHL (i have never had to queue to get on the platform etc). The walk to NP is probably 10 mins - give or take.
Edit - not sure...
If you are really lucky you can make the 22.06 if you catch the 21.32 from WHL & get the Victoria at Seven Sisters. Would be very tight though. Previous train is 21.17.
Brighton have been given blocks 35-38 of the South Lower. Not sure about the upper yet (find out tomorrow) will be a min of 3 blocks (45, 46 & 47) but probably 5, ie, 43 to 47.
I dont think away clubs always do the £50 family package for their own fans as some have been known to 'chance their arms' but from my experience, they do charge the same as us for the other tickets.