Did you get a preowned watch? What that meant was someone activated this watch on another phone using a different samsung account. They need to sign in and unlock before you can activate with your account.
I had an S3 and upgraded to S4 and S5 before jumping to Note 4 and for me it was very worth it. There is a noticeable improvement in performance plus the screen and camera is so much better. I did get rid of the stock launcher and used Nova Launcher and that felt faster overall.
Why would you want to go blind browsing Web pages on such a tiny screen? To use Internet on a non 3g version you need your phone nearby anyways so just browse on the phone
I had exactly the same issue and chose option 1 as I have no idea how to set up IMAP. It is working now and I can check and respond to emails on the watch. Thanks!