There will be another chance but you are more likely to have to get him via coupons than free. Yes Oasis knows people will try to complete him even though he isn't a game changer. It's totally up to you to waste your coupons or wait and collect his frags for free.

14. "Activity Lucky Bag" added. Complete missions to receive rewards, awesome new items are awaiting! Period: Jul 25th-Jul 31st Requirements: Players must reach Level 6 in order to participate. How To: a) Click “View Details” in the right bottom of the interface to check the missions. b) Complete the required missions to get activity points. Lucky bags can be opened with ac*ulative amounts of the points. You can open 25 bags per day in total, which will randomly drop these items: Coins, Refine Rune, Izuna Uchiha, Chiriku, Kinkaku, Sakura[Cloak], Lv2.Magatama, Seal Scroll, Stamina potion etc.

From the latest event thread.