Decide which internet streaming services you want (NetFlix, Hulu, Vudu, etc.) If you can find a BD player that will access them (most Pannys and Sonys will access all the most popular ones) you don't need Roku or Apple tv. If your BD player gets the services you want another box is just duplicating functions you already have in the BD player and taking up another HDMI connector on your set. The set you're considering (EH6000) only has 2 HDMI inputs and you need one for your HD cable box--that leaves just one left over for another source device.
The majority of sound bars will work with a digital optical input. Ignore ARC--it's harder to set up and will take up one of your 2 HDMI inputs. Make sure the set you buy has digital optical out. Connect digital optical out on tv to digital optical in on soundbar.
If you don't already have a WiFi router you'll need to purchase one. It will have ethernet connections (sockets that look like big phone jacks). One will connect your router to your modem, the others can be used for wired connecton of your computer or other wired devices. Once set up any WiFi device will detect you network during the setup procedure--you enter a security code on the device your connecting so it can access your router (you only need to do this once at initial setup, not every time you access the internet with the device). The code is usually on a tag attached to the router.
If all this setup is too intimidating you can either have a pro do it for you or snag a teenage relative to do it for you.