Sikh community is about 1500 and there is a Gurdwara Sahib in central Dublin and is open all days with Kirtan divans on Tuesday evenings and Sunday.
Ireland has a lot of investment from US multinational firms. Most of tech giants have their EU headquarters in Ireland... including Facebook, Google, Microsoft. Decent Investment banking presence as well... lot of Pharma companies including Pfizer have huge operations here. So overall job market is good for tech/science/business background people.
Irish are welcoming and there is lot of migration in recent years so you will see a big number of Polish, other EU, Indian and Pakistani population here. Interestingly most of the migration from Pakistan in last few years has been of educated people working as doctors/consultants. However in last two years they found a loophole in EU law and lot of illegal Pakistanis living in UK have been coming here to get "Pakke"..
There is some racism which I guess will always be the case in any country where you live as minority and yes it also leads to obstacles if you want to move up the corporate ladder in senior management positions. Few years ago Irish police banned Sikhs wearing Turban to join the force and Sikhs lost the case as well. Some of this was also due to trouble makers within our own community as well who are always trying to harm the community from within. So working in some of the public service with a specific dress code will be challenge for a while.
They have lot of multidenominational Educate Together schools here which are very open and no uniform and allow for al type of religious clothes to be worn. Kids don't face any problems in these schools.