I also concur that Hero+ operates auto on/off and start/stop recording. I'm using Android HLT on a Galaxy S6 Edge.
However, I too notice that when when in preview mode the PiP is not supported and I cannot view the video in HLT. Screenshots attached.
Hero+
Re: Hero+
Please do not mix up issues with connecting action cams and the general operation principle: videos recorded using an action cam need to be transferred to the smartphone before watching or overlaying them. The error message you posted simply means the video has not been transferred. Please have a look into Video Documentation (www.gps-laptimer.de/documentation) for the details.
Harry
Harry