So #2 needs some way to access Internet - cable?
That's right. As far as Roku and similar are concerned, cable is just a pipe to the internet. Whatever TV programming plan you may have with your cable provider is irrelevant. Any pipe to the internet will work, as long as it's fast enough. E.g., fiber will theoretically work even better than cable. What you want is the fastest possible internet connection.
#2 can provide you with cable TV and phone service, all in a bundle. But at a minimum you have to have Internet service via an ISP.