I use the FireStick on 2 different machines to one Amazon prime account, then I side load apps. You need to decide your requirements (mine was WatchESPN), then get devices, test, and decide what works, including for a lo-tech person. Example: One Netflix account works on multiple TVs. I was not aware of the limit of SlingTV.
My setup is HD Indoor Attic Antenna feeds all coax in house for local HD channels. Picture is much better than via other sources.
Then I got 2 FireSticks, 2 TVs, with one Amazon Prime account gives me WatchESPN and all ESPN channels live on both FireSticks.
Followed I side-loaded apps to watch other shows, and not worry about a DVR but to watch recorded shows from the cloud.
This does not require multiple accounts. But your limitations are hammered by your own personal requirements and then imagination.
Whatever you do, test before you cut. Make sure you can live with the solution.