Which background processes can I disable to speed up my Mac
I suspect there is not much you can do here. This is because most background processes only run when they are needed (see "On Demand")

Best to look at Activity Monitor to see if there is anything taking up CPU.

My guess is for text editing and multitasking you will have no speed issues. 

For web browsing the browser and especially add ins will take up CPU and memory thus requiring swapping.