Children coming out of school at 1.30 and really long school holidays.
Primary school days are fixed nationally as 5 hours and 40 mins, and can be an hour shorter for infant classes (first 2 years of primary) if the school wishes. One school might run from 9:20 - 3pm (2pm for infants) while another might run from 8:30 - 2:10 (1:10 for infants). You could see 5-6 year olds leaving school at 1:10 if the school keeps those hours.
Secondaries don't have fixed hours but generally run from around 9-4 with a half day once a week, or some have no half day but keep shorter hours like 8:45 - 3:30.
The school year in primary has a fixed number of days, where summer holidays last from end June to end Aug in primary, and start June to end Aug in secondary.
More obvious nepotism than in the UK middle classes. I know it's rife in UK upper classes, old boys network etc, but not in the circle I have access to in the UK. Where as people in equivalent circumstances to me in Ireland seem to need to know the right people to get jobs. Again, may just be the subset of people I mix with.
Not my experience. I have seen it happen in small family companies from the building / construction trade to accountancy firms, where family members fill openings, but not in most companies or the public sector.
I would say that there is a general cultural preference for personal over impersonal contacts. For example, all else being equal, a job applicant that is known in some way (and comes across well) will often have the edge for shortlisting over an applicant that is only known via the application. It might just be a case of having met the person a few months ago, or them having phoned to ask questions about the job, etc.: any personal contact is better than none. It wouldn't apply to jobs advertised in huge companies but is common enough in other domains. It's an informal referencing system - people want to know if someone is sound, a decent human being, etc. when considering them for a job.
In my experience, compared to the UK, phone/WhatsApp calls and talking to people face to face is much more important for getting things done than emails or other remote contacts. This holds for everything from navigating officialdom and arranging medical treatment to applying for jobs and finding someone to cut your lawn.
Greater interest in grooming - or example I was really surprised to find that people went for a blow dry before a funeral in Ireland.
I've never heard of this and I've been to a lot of funerals in Ireland (as most Irish people have).
In fact, you'd get some funny looks if you turned up to a funeral having obviously just stepped out of a salon.
I'd be interested to know if these are really Irish things.
Not really, apart from some of the school stuff.