eea2 route after renouncing uk citizenship

[mfhkay]

hello i need an answer asap
my wife held dual irish/british nationality she is renouncing her british nationality but she is still getting abenefit called unversal credit and she is working in kfc
she is planning after getting the renouncing certificate going to ireland and come back to activate here eu free movement right and then working another month on kfc and applying for eea2 the question
1-will getting benefit affect the application even she's working
2-does she need to change her national insurance number after renouncing bc
3-now she's working as a british , after renouncing will she be excercising treaty right if she is still working on kfc