I’ve been wondering about rooting the iFive Mini 4 (to get rid of that abysmal iFive Skin) so I’ve done a bit of research.
There are ambiguous answers as to whether or not the Rockchip 3288-based Pipo P1 can be rooted [Google Translate].
Despite not having Volume buttons, the original Rockchip 3188-based Retina-class Mini 3 was rooted and custom ROMs made available for it. It seems it was all handled via USB cable to a Windows-based machine.
So I have to say the odds look good for the Mini 4 being rooted and perhaps also getting custom ROMs.