Canada gives immigrants/refugees assistance right away, sometimes more than what citizens applying for income assitance get.

You've raised some interesting points which I can't really comment on but I'd like to research if there are arguments on those points. The functionality of UBI elsewhere I've never thought about much. I know it could work here in Canada. there'd be no difference in incentives, as already there are the free income benefits for immigrants greater than what many of them could get in their homelands even from working 24/7