Oz,
I do not quite get what you want to achieve with a 12.9" iPad Pro and a 19" TV as external Genos display.
Do you want both the vocalist and your wife to see lyrics screen from the Genos LCD screen at the same time? If so, you just have to buy a RGB splitter to split the RGB output into 2 RGB outputs, which connect to 2 TVs / LCD monitors. I personally connect Genos to 2 external LCD monitors through USB to HDMI adapter, HDMI 4x2 matrix switch (4 inputs, 2 outputs). You can substitute the HDMI matrix switch with a HDMI splitter. HDMI is more compact, convenient and advanced than RGB connections.
If you want to use the Genos registration to bring up music sheets on the 12.9" iPad Pro using Songbook+ for your vocalist, whereas your wife continues to use the Genos LCD screen plus external LCD TV, then you will have to choose one of the following options for the iPad Pro of your vocalist:
1. Wired solution: Buy a Lightning to USB camera connection kit, and connect your Genos to the iPad Pro using a USB to host cable (aka USB printer cable) betwen the "To Host" port at the back of Genos, and the USB port of the Lightning to USB camera connection kit that plugs into the Lightning port of your iPad Pro.
See page 4 of the following document for concept and diagram:
https://usa.yamaha.com/files/download/other_assets/6/725646/iphone_ipad_connect_en_i0.pdf2. Bluetooth wireless solution: Buy the Yamaha MD-BT01 Bluetooth wireless MIDI adapter and install it on Genos MIDI B In and Out ports, and your iPad Pro will discover it and connect to it.
There are also other third party bluetooth MIDI adapters that you can use. I tested and use Yamaha MD-BT01 since it is one of the 'official' accessories of Genos.
Thanks,
Paul