What is the best way to get from terminal 1 to terminal 5 at 10pm in mid February? The connection is on separate tickets so I will need to collect and RE check luggage, and get boarding passes. Uber??

You can use Airport Transit System (ATS) from Terminal 1.

I recommend you sign up for TSA Precheck. It will help you check you luggage faster. You can sign up from the TSA website. About traveling between terminals you can use the airport bus shuttle service.

Take the shuttle inside the terminal its a golf cart i did if are disabled.