Is the bishop pair and a pawn equivalent to knight and a rook? In theory, rook (5) + knight (3) = 8 points. 

And bishop (3.25) + bishop (3.25) + pawn (1) = 7.5 points.

For example, do you think black is better in the following scenario or do you believe white can hold with good play?

[fen "1n2k2r/ppp1pppp/8/8/8/8/PPPPPPPP/2B1KB2 w - - 0 1"]
It's an oversimplification to think of the bishop pair to be worth 0.5 points on average. There are cramped positions where a bishop is barely better than a pawn. It's very difficult to generalize based on your question, it will vary greatly from position to position. But in case you're only interested in an "on average" answer, then the side with the rook has a slight edge.