No, they won't. While Gumi may be stupid enough to do something like that, Alim certainly is not. Unlike in the west, gacha games are an extremely competitive market in Japan. That's why they hand out so much free stuff. Putting Cloud, or any other FF fan favourite units behind a paywall would doom the game, because people would just move on. Just have a look at the Japanese app store to see how many F2P final fantasy themed games Square has on offer. There would be plenty of alternatives *within the FF theme* if Alim screwed up.