There are 2 places in Haneda Airport where you can buy Muslim-friendly souvenirs.
The first place is Edo-Shokuhinkan.
http://www.haneda-airport.jp/inter/en/premises/tenant/5200100012750000/index.html
The second place is LAWSON.
http://www.haneda-airport.jp/inter/en/premises/tenant/5200100012200000/index.html
There is a variety of line-ups including castellacakes, rice crackers, and chocolates.
We recommend you visit here if you forgot to purchase souvenirs.
