[otnt]

...it really would need to, in this day and age work with both Android devices and iOS devices.

Not really sure why iOS is mentioned (and discussed) when MobileSheets is clearly Android app. Apple boys have tons of apps with multiple iPads control.

Often times different instruments will have a charge paginated in a different way, meaning the pages turns aren't always at the same time.

1. I'm making my own sheet music
2. It ain't so difficult to rearrange pages to "be on the same page"
3. Ensemble/band sheet music on tablets is 90% for gigs and teaching. 90% of this sheet music would be suitable for multiple control.

You will have to decide which method you want to use; bluetooth or Wi-Fi.

I hope to be able to TURN SHEET MUSIC "hands free" as most of the musicians do use both hands while performing. All wireless turners I know are Bluetooth. Please let me know if you know about some Wi-Fi wireless page turners. In this case I would get Sony DPT-S1 and I can forget about android apps to TURN SHEET MUSIC "hands free".

Wi-Fi has a much better transmitting distance...

This was discussed five years ago at the iOS forums. Since then most iOS developers are using Bluetooth. Most of the places are cluttered with interfering WiFi signals. WiFi is dodgy in this case. It is advantage to use localised little Bluetooth network. And Bluetooth 4 is ultra low power.

...not all Windows devices have bluetooth...

Not really sure why Windows is mentioned but you can get tiny BT dongles for Windows devices.