The standard remote has an INTERNET button which takes you to the "Viera Server" which essentially brings you to TV apps. This is assuming your TV has an internet connection. The easiest way to have a connection is directly through ethernet since the TV is only WiFi READY (it requires an additional device to use WiFi..... oh marketing)
There shouldn't be an echo if you are using HDMI through your Media Player (Bluray, PC, Mac, Roku, etc.). The only time you experience any sound echo is when the TV volume is on and the external volume is on. One way to ensure this does not happen is to use the MENU button on your TV remote and go to the SOUND properties submenu. From there you should turn you TV SPEAKERS to OFF, thereby ensuring that only the sound that is fed to your eternal speakers is the sound you hear.
I would not go that way. I thing your best way would be with a WI/FI KB. However, you have to be shore that you have the adapter connected to your wireless link to your IPS. In other words, yes, you can do the kb with the proper compatible equipment. (You can buy the adapter in Amazon, and it works perfect.)