Personally I thought the film wasn't bad in many ways but there were a lot of inaccuracies. The death of Harry Boland, as you say, and the car bomb! I looked up the details of the planning of the Custom House last night, and it seems that at the initial meeting, Dev asked for a major gesture. He proposed either Beggar's Bush or the Custom House, and the details were left to Oscar Traynor to investigate. The plans were then worked out by a kind of subcommittee in which Collins was involved but De Valera wasn't present (though Mulcahy was). One thing I have wondered about is the business of the Local Government Board chairman hearing about the attack in advance. The security was very tight and the people who carried out the attack didn't know what the target was until the day of the burning, apart from a handful of people. Is it possible that someone leaked the details to delay or prevent Dev's gesture ...?

No evidence, but it's a thought.
Thanks for the name of Daniel McAleese. I've just looked him up on Google and he was definitely there on the day. He was one of the tax office employees, apparently, so I'll add him to the non-military list.
