It's usually mozzarella or cheddar that's substituted for curds, yes.

Oh, okay. Curds used for poutine are technically mozarella aren’t they? I think I have always assumed that because they are white and mild, but never really dug deeper into the thought before. Maybe I am way off base.

Anything that melts easily doesn't work. In theory a frying cheese like haloumi or queso frito cheese might taste good. They're usually salty enough and have the right texture. I've not tried it but they may make for an interesting substitution as opposed to a clearly inferior one.

Oh, sorry if my wording was confusing. I didn’t mean I like soft cheeses on poutine. I just meant I only like mozza and soft cheeses in general, either by itself or in a dish. I got off-topic and didn’t make a cue. Still, I appreciate your thoughts and those are good theories, even if that’s not what I meant haha :)