I don’t know about the scroll to a specific list item other than to suggest using anchor scrolling.
As for coming back to the previous position, spend some time reviewing the docs for $ionicScrollDelegate:
Beta : http://ionicframework.com/docs/api/service/$ionicScrollDelegate/
Nightly : http://ionicframework.com/docs/nightly/api/service/$ionicScrollDelegate/
Look here too : Accessing scroll position