The reasons why the ROL applications can't be ported to RISC OS 5 have been stated time and time again: they rely on new features of the OS to provide their enhancements that CTL's RISC OS does not have.
In terms of porting an OS, nobody other than Castle has managed to write an on-the-metal OS for the Iyonix. Both Linux and NetBSD depend on RISC OS having already set stuff up. Castle need to provide documentation for their hardware to let other OS authors port their operating systems to the Iyonix. I don't spot any such details on their web site.