Is there any way to customize the interface for Android, as I want to?

Ok, what I want is simple, I want to add filters to conversations and messages on android, I don't know whether I can't or not, to modify the screen for calls and messages to run both at the same time, on half for messages one half for calls.To add a shortcut for the password to not introduce it every time time Phone runs in standby. Also how can I modify the life span of the battery, so that if it runs lets say below 30 % it turns into power saving mode, disables internet, and all apps that consume power. Also for when listening to music or browsing the internet, how can I open music in background of my phone and still browse the internet without closing, 3 or more pages at once?

All I want is to configure and modify the interface and manipulate it as I want. Is there any software or settings, from which I can do this?