How Does Android Detect USB Connectivity and More About USB
It is based on port detection, which involves both power and data for a conventional USB connection. See Android USB Charging Secrets and Overview of USB Battery Charging Revision 1.2 and the Important Role of Adapter Emulators
When it comes to OTG Y cable, which requires powering and data transfer as visualized by you, I don't think it will work without modifications to the cable . Reason: You are attempting to marry USB standard with USB on the go standards. The D+ and D- pins which are used for power negotiation (as described in the links above) are not available for data transfer
I haven't played around with OTG Y cables much but this question on Electronics sister site shows the modifications that are required to be done Can an Android tablet serve as USB Host and be charged simultaneously through a single port?. See in particular, Guide..OTG USB HOST and CHARGING at same time for Galaxy tabs.. by MRBR7 XDA post quoted in one of the answers


Interesting question and do post your answer with your findings (yes, answering your own question is encouraged)