You would need to contact the Irish embassy in your country or the Irish department of foreign affairs in Dublin. Either of them would give you the information you need. They can go through your specific details and give you the information appropriate to your case.
No. Limerick is not in Britain, so a British visa has no relevance there. Limerick is in Ireland. You may need a visa to go to Ireland. That will depend on things like where you are from and Ireland's visa arrangements with that country.
Yes, you need a separate visa for Ireland. Ireland is not part of the Schengen Area. Schengen visas are not valid.
Unless you are a citizen of a country that has a visa-free arrangement with Ireland, you cannot enter the country without one.
Ireland
Ireland is not part of the Schengen Area so Schengen visas are not valid in Ireland (or the UK). You may need a visa unless you hold a passport from a country which doesn't need a visa for Ireland (e.g. USA). Check the Irish embassy for your country to see their rules.
It can depend on where you come from. Different countries have different arrangements. However, generally the visa system used for Ireland does not entitle you to go to Britain. A separate visa would be required.
Yes.
Yes.
it took a long time
Ireland is not part of the Schengen Area. Schengen visas are not valid.
With a UK visa, you can travel to the United Kingdom, which includes England, Scotland, Wales, and Northern Ireland.
If you are just visiting no they will give you a 6 month visitors visa at the airport