Is it possible to grab 3 people with 3 computers, make each one a miner and "sign"/"confirm" a BTC transaction that is pending for 4 days?

Who are those people who "confirm" the BTC transactions? Can anyone become one of them?

If so - why not PM them your pending transaction and get it confirmed?

If not - where are all those stories about miners "moving to Bitcoin Cash" coming from? Where is this info coming from? Who really controls the data/information or the real stuff behind Bitcoin?