Here is what the Gunners have to say on the matter of scattering cremation ashes at the Emirates Stadium…
Ashes are not interred or scattered at Emirates stadium.
Also, there is no memorial plaque within the Stadium for individual memorials. The board arrived at this decision after much consultation and had investigated many different avenues. However if you visit the Arsenal website; https://bookings.arsenal.com/stones/northbankterrace/stones/book.htm this gives you and opportunity to personalise a granite stone in memory of your [loved one] which will be placed outside the Armoury in the near future.
It appears they do have some form of memorialisation – https://celebrationcorner.arsenal.com/ which is a step in the right direction
This information was correct at the time of publication, organisations can change their position so for the most accurate information please contact the origination in question directly.