The R2 has an mt7623 which is for sure not a phone/tablet SoC...
Actually, the R2 is quite well mainlined.. Not perfect but most features 'work' on mainline. I'm quite sure both SoCs could be maintained with one kernel (similar as we do for Sunxi in mainline).
CSC boards for a SoC which doesn't have any wip or supported boards is IMO pointless. As shown in the 2G-IoT, nobody cares and maintains those boards/kernels. IMO this doesn't make sense, better the users chose a distro which maintains the board as they stick to a csc armbian which doesn't get maintained. Cause both SoCs are well mainlined I still hope that other boardmakers pick up these SoCs for some boards. Something like a HC1 could be made out of it..
The page is not done yet and they just copied it from R2. Actually the kernel is 4.4.92. I think they mean the 4.14 kernel from OpenWRT
But it's maybe 80% mainlined and the rest is in OpenWRT (except for HW NAT because they don't support that for any SoC).
Because of this I think it is very likely for this board to be a stable CSC (unlike R1/R2).