2). Yes, but I don’t have an iPad to test if Bluetooth might be an alternative to USB.
Yes, it is possible to connect two H90’s to H90 Control on an iPad and Desktop computers. Both device serial numbers appear at the top next to the Home tab, and we can select the view by clicking on either. On desktop computers it’s even possible to click the arrow icon to detach the device’s tab and view it in a separate window.