Which exchanges are supporting it?
I think at the moment two exchanges are supporting the Bitcoin Interest Fork - one is HitBTC and the other is Okex. I am not % 100 sure, if I am wrong please correct my mistake.
That's true and correct because I follow this project and I read their announcements about the two trading sites which will support this bitcoin interest. This will be the third fork to be happen this jan. 22 so I hope after this fork we can see some major changes in terms of their transactions and fees.
The founders command can be will be able that or to change up to 22 january. They still have some time to do this. Other platforms too will be possibly used. In particular, interests bittrex.