I downloaded Minecraft and Tricky Towers on one of my accounts and it was accessible for both accounts I had. I made a new adult account so I could get PlayStation Plus, and then deactivated my others. The games are on the PS4 but I have to get the full version of Minecraft, and redownload Tricky Towers. How come this happened? I don't understand why I can't play the full version on the account when I reactivated it.
If I am understanding this correctly, you now have two different accounts: Account A that was a child account, and Account B that is an adult account. And going off what I can understand, you deactivated the Child Account and activated the Adult account. If the child account was the account that bought Minecraft, then that is probably why. Deactivated accounts can't share their games with other users until they are reactivated. Try activating the child account again and seeing if you can play it again. You should be able to have multiple active accounts on PS4 (I think Sony refers to them as Primary, not Active, but don't quote me).
(Also, if you had PS Plus in the past, it is possible that you got Tricky Towers for free, so that would explain why it is a redownload, not a full purchase. I know that is kind of off-topic, but figured it may help)