Re: Ability drops in packs
Unfortunately the random system which they use to determine what is in any particular Sticker Pack which you open is truly completely random; it does not appear to take into consideration what you did or did not receive in previous Sticker Packs and clearly is not programmed to offer anything in particular on any sort of "schedule".
Because of the completely random nature of the system it is possible to have "Lucky Streaks" where you receive the desirable stuff very rapidly or regularly and it is also possible to have "Unlucky Streaks" where you get stuff that you have no interest in over and over again.
You'll find plenty of stories from Players spending tens of millions of coins trying to get one particular Sticker and you'll also find stories from Players like myself where the system seemed to not be able to give desirable items to fast enough.
It's so determinedly random that nobody can reliably say how many Sticker packs you'll personally have to open before you receive all of the alternate abilities which can be obtained through the purchase of Packs.