A VFR/SE operation along these lines will be very weather limited, and and I speak with many years experience of flying on public transport ops all over Ireland using the mark 1 eyeball, long before the regional airports and navaids appeared - but maybe they are hoping to get approval for GPS approaches - IFR in a single???
If the intention is to operate tourist /sightseeing flights in good VMC there is probably some seasonal upmarket demand, but I doubt that SE overwater public transport ops to the Aran Islands are legal, even in a floatplane.
They will need a twin eng floatplane to address the IMC and overwater issues
I wish them luck, but...............