Judging that shisui susanoo is a premium ingot ninja - he will most likely not be in fuku deals. Like what the two other players mentioned, you would make a rookie move in thinking to you could spend all your coupons thinking you are guaranteed a ninja for these types of events. A f2p will not likely have a premium ingot ninja anytime soon and the only way is by luck or they become available via coupons (but the price will be 40k+).

If you had enough coupons to complete a ninja via the redeemable section such as kimimaro halloween or hasirama CNY for this week, I would try to complete it via lucky stars in hopes you could get lucky getting the jackpot prize that way you have at least one ninja rather than no ninja. However, since you don't have enough just wait until you save 25k+ coupons to prepare for fuku deals when you have enough to spend.