Ireland (Re: Freedom of movement.)
Ireland already has a series of bilateral trade and free-movement treaties with the United Kingdom that predate the EEC, and many newer ones (e.g. Good Friday agreement) that are not conditional on EU membership. Brexit won't affect these. The fact that neither Ireland nor the UK has a land frontier with any other EU member would make it possible for the UK and Ireland to continue to honour those treaty obligations even if one nation left the EU.
The economic effects are generally considered to be neutral to Ireland overall: negative in the short term, but potentially positive long term as the UK effectively removes itself from the EU foreign direct investment competition. Short term, an exit will increase the administrative cost of trade, but not necessarily its volume. Ireland's main exports to the UK are in sectors where sourcing a non-EU substitute would be problematical (in order of revenue, those are: Pharmaceuticals/cosmetics/ingredients, then food/dairy, then plastics/machinery/electronics - only the last of these is easily sourced from other countries). Plus, aside from the big pharmaceuticals companies, these aren't big deals, but thousands of small to medium sized companies trading with each other.
Longer term, Ireland has a small possibly of benefitting economically from a Brexit, particularly in Financial Services, although not anywhere near as much as a Brexit would benefit Frankfurt. A City of London that's outside the EU loses one of its big advantages to external investors.
Now tho the "Stay" campaign's scare-tactics: In the event of an exit, the UK cannot rescind residency to EU citizens already in the UK - doing so is against international law, it is a bureaucratic nightmare (especially in a country like the UK that does not track the residency of EU passport holders) and it would also cripple the country's economy for a generation. Many could choose to leave, but they couldn't be forced to.
Ireland has a good lesson to give here on the dangers of sending people "back where they came from": in the 1930s, many of the Anglo-Irish were "encouraged" (often violently) to leave the newly-independent Ireland, and it resulted in a country whose economy was on par with Denmark's in 1922 falling to the bottom of the European league table by the late 1950s. (Northern Ireland's status as the UK's economic basket-case is similarly founded on the misguided belief that national identity is somehow related to effectiveness as a worker)
Biting the hand that feeds IT
