I can see perhaps one of them playing the 8 in a similar way to how Matt O'Riley does for Celtic, but no chance of both.
Bissouma is perfect for the McGregor role, absolutely. Good and comfortable on the ball, happy to receive it from the centre backs and turn and good at breaking lines with his passing.
Celtics #8s tended to drift out wide, which is where I think Kulusevski could excel in the role. Not only would he be able to creative from the middle, but he can also go out wide when the inverted pull back moves in to offer a bit more superiority in the middle.
I just think playing Maddison and Kulusevki in a midfield three with Bissouma behind them would be as stupidly naive as ten Hag was when he thought playing Eriksen and Fernandes in a midfield three was a good idea too.
I think we may see something different from Ange though tbh. Kane isn't his typical striker (Though funnily enough Son would be). So I have a feeling he will be giving us something different to what we saw at Celtic but within the same high energy, high pressing philosophy.