All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
We will start our answer from your last question, which is about the term ‘revive’. Revive means helping an injured and rescuing him from death; there is nothing wrong with this expression as the Quran expressed saving a life by the word Ahya, which means revive, or keep alive. Allah Says (what means): {And whoever saves [Ahya] one - it is as if he had saved [Ahya] mankind entirely.} [Quran 5:32]
As for buying packs with real money or imaginary money that has a real value, then this is forbidden gambling and it is not permissible because it is not known what is in the pack: it could be something worth a high value and it may be worthless. What fluctuates between two possibilities, either winning or losing is considered gambling and it is not permissible.
Also, getting more packs by increasing the number of matches is not free of Islamic violations. Even if it is free and does not involve spending extra money, simply increasing the number of matches would mean spending more time on the game, and this is a waste of time and it can lead to distraction from fulfilling an obligation, or to committing what is forbidden; so it should be avoided.
This is one of the tricks they use in order to attach people to the game and make them spend more time playing it. Indeed, a person will be asked two questions about time: about his entire life span, and about his youth time in particular. The Prophet said: “The feet of a slave will not move on the Day of Judgment until he is asked about four things: his life span, how he spent it; his youth, how he consumed it; his wealth from where he earned it and where he spent it; and about his knowledge how he acted upon it (or taught it).” [Al-Bayhaqi and Al-Albaani classified it as Sound]
As regards getting packs through the so-called “Squad Building Challenges”, then this is not clear enough for us in order to issue a ruling about it. In any case, regardless of the prize that one gets, it is safer to avoid all this and not to waste time on it, especially for the adults. Time is the capital investment of the person, and if one spends it in what does not benefit him, then there will be no time left for what benefits him, and his entire life will be wasted on what one will regret later.
Allah knows best.