Android SDK Version
I downloaded Android Studio and downloaded SDK Platform/Android 8.1 (API Level 27)
A bit of Google searching helped me find out that the 'tools' directory of the SDK was incompatible, and I had to download SDK Tools v25.2.5 from http://dl-ssl.google.com/android/repository/tools_r25.2.5-windows.zip (Source) and then replace the directory.
I found the solution for manually installing and updating ADB at www.xda-developers.com/install-adb-windows-macos-linux/
Installing to Device thru USB Debugging
I'm assuming this is an issue because version and product info were unchanged, and it attempted an update. Don't quote me on that.
The solution was pretty simple: Delete the old version from the phone. Other developers also mention that the issue may be that the phone itself is out of space to store the game.