1. The BF second stage (86BF) no need to use in close block circuit because breaker already trouble to open. Breaker 'b' contact already serious in closing circuit if breaker is in open condition it will not allow the closing command to CB.
2. The trip setting of Tie breaker should be less then the trip setting of other to Incomers
Because if any fault on tie breaker side then Tie breaker should trip first and save the incomer voltage.
