Nah,
No switches, been there, done that. Oil trap is just a plastic bottle.
As a matter of fact one could buy a closed oil system for aircon but more expensive. Way more powerfull to suck the air out tho.
It is simple, really. Do not over think this. Any fridge fixing shop can sell u one for almost no money. Most of broken fridges have no gas in them, hence broken
The pump is designed to run continuously, it goes warm but thats ok. Better to run all the time than loose a vacuum. Loosing a vac is more expensive, it might ruin the project. Your call...