What you experience is probably that you have changed the browser and search language
Settingsv -> region+language -> Browser & search language
Set it to English(United Kingdom) for example and then you won't see bing be opened in IE but "as an app"
Unfortunately it is currently not possible to search for settings. Microsoft knows this list is getting out of hand and Joe Belfiore has hinted that the next version of Windows phone will deal with this issue.
In the meantime it is possible to pin some of the settings to the start screen using 3rd party apps or accessing them through the notification center....
As far as I know, both of those games require 1 GB of RAM(1), and the Lumia 520 only has 512 MB. So that's the reason you're not able to find them in the Store. This should be standard behaviour - apps that aren't compatible with your phone for whatever reason don't show up in searches.
You can always search for the app at WindowsPhone.com, or open the ...
This might be a bit difficult. To do this you will need Windows Phone 8.1. Hit the search button and depending on your location you might get either Cortana or Bing Search. Type in the keyword you want to search for and search for it. Cortana or Bing will give the results from the web. Swipe left to the phone section and it will give you the setting or ...
The Bing Vision app is obscurely available under the camera app.
First open the Camera application, then click the settings icon, to open this view:
Click on the Lenses option, and...voila
Bing Vision will be available, amongst all the other lenses and camera related applications, as shown above.
No, at least not yet and not even on the final WM10. If you have Cortana in your country you can ask her to id music or even shazam a song but the Vision and Music functions are currently not implemented which is a big shame as I you now need 2 more apps in your phone to perform these tasks (Shazam - SoundHound - Musicmatch.. and a QR reader like QR Scanner)....
Unfortunately there is no such mechanism for searching text msg. But, you can refine the msgs and call by date. Go into Contacts, select the intended person and then swipe left to history. This might help you a little bit in refining and sorting the conversations by date.