Ok I tried to flash the plus version in my pro with intel flash tool.
It worked to flash, got some error messages at the boot but they were small, probably because its a pro and not plus. It booted into RemixOS and everything worked, except one big thing: the rom dosent recognise the battery, if I took out the USB cable the tablet just power off, the battery meter is always at 0%.
I mailed a RemixOS developer about this, they said they couldnt do anything about it because Intel havent released an Android BIOS for Z8500 :/