When you are not actively using Safari or Chrome, but if they are in the background still with open tabs of websites that were visited while in the foreground, do they keep refreshing and sending my IP address etc. to the websites? (iOS)
Unless you have Background refresh turned on for Safari or Chrome, they don't.
Note that when you minimise a app, the app just stays in Stand-by mode. When you again use it, it refreshes the data by sending your information again.