About using vibrate for feedback in your example, AFAIK, there is no public API. If you don't want the risk, don't take it. Use the bug reporter if you like to make a feature request.
About 'AudioServicesPlaySystemSound' ...from the docs:
"You can use System Sound Services to play short (30 seconds or shorter) sounds."
As KMT correctly points out, there isn't public API for invoking the haptic feedback used in 3D Touch. It's a commonly requested feature, which you can add a +1 onto the pile by filing a bug report (we do pay attention to the number of dupes that bug reports get). It would not be appropriate to use undocumented arbitrary values in APIs, so I would recommend you not do that in your submission.