I haven't checked for sure, but I wouldn't count on ROOL being able to release any fonts other than the usual ROM ones. The issues with running with UTF8 as the system alphabet is now largely an issue for application maintainers (nudge nudge) although you usually find that printing and splitting strings comes "for free" as long as you use the usual font manager SWIs for it.
What you'l find usually needs attention is editing and navigating through UTF8 strings. The RISC OS 5 Wimp goes to some pains to handle this, including malformed UTF8 strings, in a manner that matches the font manager's display - look at skipcharL and skipcharR in RiscOS.Sources.Desktop.Wimp.s.Wimp05 for how it does it.
The ROOL versions of TextGadgets and Draw are still in need of converting to support UTF8. There's also the thorny issue of the system font: there were plans at one point to make it fully support UTF8, but to do it properly it needs to support single- and double-width characters (for Japanese) and probably needs to move to 16 rows high too. The cursor copy algorithm would also need some work to make it more efficient to read from the screen when the number of possible characters is from a much larger set than a mere 224.
There also used to be a Unicode-aware version of !Chars kicking about, but I notice the one released by ROOL so far seems to predate it. I sense some digging is required...