My house is a safe space for DC’s friends to visit. The main rule I have made with DC is that any discussion is respectful.
He and I disagree vehemently about a particular subject and rather than go through a heated debate every time, now I stop him and say “I won’t get involved in this discussion because I believe the problems you’re raising stem from it being a bad idea to begin with”
He can believe what he likes but I won’t problem-solve for him when IMO the problem is the belief itself. So far its reduced arguments on that topic by 100%.
I occasionally get ‘sounded out’ but the fact I’m consistent and he has to problem-solve himself means he has thought more carefully about the topic, not just jumped straight to being defensive and more entrenched.
Of his friends, I use names to avoid pronouns where necessary and try to reply honestly as tactfully as I can.
Pre-lockdown #1 I overheard them in the garden having a gentle exploration of it maybe being better to just be yourself with no pressure ‘like here - your mum never cares and she wears some weird shit herself’
I’ve never been so happy to have my dress sense questioned 
So my advice is, you can be respectful by using their name, and/or pronouns, and keep a boundary about discussions so things don’t get heated but you aren’t ‘pretending’ to keep the peace.
I still disagree on one specific aspect with DC however he and his friends know they can be themselves here without the need to form arguments/defend positions.
From my limited experience they want to be themselves more than they want to ‘be right’ and given that safe space they soon question stuff themselves.
The defensiveness when they are challenged reminded me a lot of when I was questioned about my abusive ex, I did not want to be forced to defend him but I was too scared of the consequences if I didn’t.
It was only in a safe space that I could start to really think about his words and actions and their impact on me, for myself
So that’s what I try to bear in mind with DC & co.