So what's Ireland like in this one?

[Maeran]

As far as I know there are no region specific units in the British Isles, so Ireland produces exactly the same units as the rest of the British Isles. It is only still a beta release (an amazingly solid one, but beta) so hopefully more regionals are something we will see in the future.

I don't think that anything resembling the Irish units you mention will be reintroduced, since they came from the Goidelic south of the island which is unconquerable ("Eremos") in the present build and highly likely to remain so.