Adafruit LiPo charger + On Off SHIM?

I’m building a Pi Zero W for my sis. She wants it to watch ESPN3 and such (MotoGP and others, too). She has no real enthusiasm for learning Linux so I want to build a “painless” system. Use the SHIM for voluntary shutdown plus a LiPo “UPS” to survive the inevitable power drop. If the battery goes down too far I want to shutdown. Is this realistic or is there a better design? I’ve architected multi million dollar software projects but I changed majors from EE to CS (in the 70’s!).