There's nothing in the articles above to say there'll be any restrictions on how the remaining slots are used. And how could Aer Lingus provide any meaningful competition against BA on Ireland-Heathrow routes with just 4 slot pairs?
I don't know but if I was part of the EC investigation team it would not look good from their point of view for BA to being given 100% control of IRL-LHR market. I see no other reason why FR would want to keep them.