Travelling to PC with teenagers that are not mine

Hi everyone. My family and I are going to PC in December coming from Canada. My daughters are each bringing a 17 year old friend along. I've been reading conflicting posts on different platforms regarding notarized consent letters from their parents. Some are saying letters signed by a witness are enough and some are saying they need to be notarized. I emailed the DR consulate in Montreal yesterday but they weren't really helpful as their answered pertained to children of DR origin (not the case). Anyone have any experience and what documents were required?

TIA