No, but double check with the coach operator.
No.
Yes you would need a passport. You would also need a visa.
no, as long as you have a passport
If you are talking about Euston Station in London, to Dublin port, then it would be an international journey so you may need a passport. It will depend on your nationality. If you are talking about Heuston Station in Dublin to Dublin port, then it is a journey within Ireland, so that journey itself would not require a passport, but you may have needed one to get into Ireland in the first place.
no you dont
You need a passport to enter any country, that's why you have passport control at airports.
yes. which ever way you leave a country, u need a passport
definitely, yes
As the "Common Travel Area" is in place, you do not need a passport to go to Dublin from the UK. When flying between the UK and Ireland it is best to ask your airline what form of ID will be accepted.
No
That will depend on various factors, like your nationality and what your requirements are for getting to England.
NO