Interesting - my sources suggested that these were entirely separate projects. Nothing at all of the old station will be anything to do with the new terminal, which in any case is slightly off to one side. Listed building or no, the main line network is awash with old stone buildings now locked up and uncared for, with buddleia growing in the stonework and cracking it, and roofs leaking. Clearly, if old buildings are not actually in daily use now, there seems to be no funding to care for them. And in reality, in cold, hard practical terms, the government subsidises IE to get people from A to B, not to look after historic buildings. That, one could almost think, would be one for the OPW.
Against that background, it is hard to see ho the Foynes relaying project could have anything whatever to do with any restoration of the Foynes station building.
Now, it may very well be, and hopefully it is, that they've combined the two - the actual railway, plus, as a separate issue, a listed building. But given the background, it's hard to see the two being connected.