Probably should also be mentioned this has been an issue going on nearly 3 weeks now with the same thing–Minecraft gets to 79% and then hangs on download. We've tried multiple times with multiple restarts, one factory settings reset, and one cache partition wipe. Even tried multiple google accounts behind the Play Store login just in case there was an issue there.
As mentioned in my original post, I've even done a complete hard reset of the entire phone back to factory settings in addition to doing a complete wipe of the cache partition via the BIOS. This is an issue inside Play Store that is affecting Minecraft only. All other games and apps download just fine, and there is no issue with the internet connectivity.
Whatever update happened to the game fixed the problem and it now downloads and installs perfectly, thank you! My son is super excited 🙂