A little OT, but . . .
I realize that the OP would like to make good use of his large stash of Avios, but if the multi-carrier redemption does not work out, perhaps he could amass a sufficient amount of AAdvantage miles for at least a one-way to or from TYO. As a Canadian resident, he could earn AA miles through credit cards (Diners Club or RBC Avion), and by crediting upcoming cash oneworld flights, if any, to AA. JFK-TYO in F on JL is a relative steal at 80,000 AA miles plus $5.60.