The 8570 does not support Airprint/Mopria, so the plugin can't work.
Xerox is a MOPRIA partner so that cost should not be an issue, but Mopria is a selling feature for the 8580 in comparison to the older and no longer sold 8570, so that may be a limiting factor.
The only real avenue you have to get the plugin to work is to do a FER on the 8570 (Feature Enhancement Request), just understand that they may choose to not implement it since the machine was already replaced with a model that supports it (8580)
Are there any workable solutions to getting support for the Android Xerox plug in to support the ColorQube 8570N? Doesn't seem to me that adding support for this printer should be too tough. Thanks!