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No, not if she has an Irish passport. If she only has an SA passport, then she would need a UK visa.1. As a Irish citizen, does she need a visa for N. Ireland?
Not sure what you mean by 'free'. There is currently no border control, but again, imperative that she uses an Irish passport if entering the UK. She needs a visa if she is using her SA passport.2. is travel accross the border w N. Ireland free, or strictly regulated?
For the Republic of Ireland yes. Northern Ireland is part of the UK and has different requirements and rules.3. When she arrives in Ireland, she shd apply for a PPS number and a card, right?
For Republic of Ireland??4. she will likely be earning minimum wage, so she shd be able to get a medical card, right?
Yes.8. as a citizen, she will be entitled to open a bank account, get a driver's licence, etc, right?