The investigation will be conducted by the Air Accident Investigation Unit (AAIU) of the Irish Dept. of Transport, but the AAIB will also have an input, representing the state of registry, the UK. I don't understand why the UK's conduct of the inquiry might lead to the airline not surviving? Standards are no different and the AAIU will not pull its punches.
The aircraft may well be an insurance write off, but it does not appear to be too badly damaged. Sea-water related corrosion may be the main concern.