I would meet with him. The constant stress of ‘What should I do?’ and ‘What if I bump into him?’ would be worse for me than anything he could say or do. I’m much better when I tackle something head on.
I wouldn’t take anyone with me, because that could be uncomfortable for him and make him defensive, I’d just meet him in a very public place like a coffee shop.
He is most emphatically NOT going to be the Dad you always wanted (and deserved 🌷) so try your best to get your head around that. He’s the person whose sperm helped to create you, he might answer some questions, some you didn’t even know you had, he’s your father, but not your Dad. Sadly, you didn’t have a Dad and will never have a Dad, try to think of him as your father, a biological connection.
I’d like to kick useless fuckers like him to the moon and leave them there. They don’t deserve to be able to reproduce and leave lovely kids without a proper Dad.
Also, don’t worry about accidentally saying anything about the rest of the family. For sure don’t deliberately discuss them and I understand their anger and not wanting him to know about them etc, but if he wants to find out about any of them he can. It’s not difficult in this day and age.
Always, always, remember you have half his DNA but you are NOT half him, you are 100% YOU 🌷