I think I'd have to pick people that I think I'd get on with or who would be interested enough to talk to me/other people I might invite even though I'm a total nobody 
if it is just getting four comedians together who I find funny, I would rather watch them on telly.
So I'd probably pick
Stevie Martin - because she was amazing on Taskmaster and her podcast described so many experiences that I thought only happened to me.
Russell Howard - he used to live in the same town as me so I know a few people who bumped into him and said he was down to earth. He also seems good at talking to anyone and everyone, and I've always enjoyed his programmes.
Bridget Christie - again I know her from Taskmaster but she made me laugh so much and reminds me so much of my mum I think they would get on.
Rhod Gilbert - partially to round out the ages and genders, but I loved his transition from his earlier very funny angry ranting Welshman comedy to his more thoughtful later stuff. Would also love to chat about adult ADHD diagnosis and my memories of visiting my grandparents in Wales, they lived near to where he grew up. I'm certain he would understand the sheer excitement of the Tesco Extra opening in Camarthen in about 2004/5 - I remember my mum's cousin being convinced that they employed shop assistants on roller skates to patrol the tills in case you had forgotten anything because it would hold everyone up if you had to traipse back through this impossibly enormous store, but they had memorised the layout and could zoom off and fetch the item. I have no idea if it was true but I thought it was brilliant.
Now I want to look up whether there is anything with all four of them in it at the same time.