I would tackle the passport flushers first. You can't enter any country if you don't have a passport. My friend ended up in detention centre in Canada because he couldn't log into his bank account to show he's got enough money for 2 weeks holidays., he was released once he sorted it out. In my view, detention centre should be opened and everyone without passports locked up until we find out who they are and where are they coming from. They shouldn't be on the streets, full stop.
Next I would tackle homelessness and "homelessness". We have a lot of people that could live with their parents short term until they better themselves, but they decide to declare themselves homeless to put pressure and get so called "forever" social house quicker. Some even decide to make a lot of babies in hotel rooms, hostels etc. Genuine homeless people have to be looked after first, the ones that genuinely don't have any choice.
Housing supply is next, this one is the toughest. There is no magic wand that would fix this, I would start from ridiculous planning requirements, plenty of people would be more than happy if they could build nice log house for a fraction of the price, but our planners are idiots. If Scandinavians, Swiss, Austrians, Germans etc. can live in those type of houses, why Irish can't?