I'd go with: Smart, Brown, Tatum, Grant, Al against Miami. I think this is a series where Grant can shine as Miami is smaller, but that still gets Tatum at SF. I also think Al will do fine against Bam. Rob comes in for either Al or Grant depending on how it is going. Grant can also spell Tatum/Brown against Butler on some possessions and hopefully wear him down (something Rob can't do except in help situations) and with Love no longer be an effective post player I don't have the concern about Tatum wearing down guarding him.
I'm starting the free Grant Williams petition now.