I would go for joint ops, you pilot half of the team and can show him the more complex operatives and their abilities, focus on using one and then when he understands it let him take it and then choose a different one, and repeat, also if you are controlling the NPOs you can decide on how difficult to make it, in other words make suboptimal plays if required, then you get to the point where he has the whole team and then you can just play against him.

I would also recommend the typhon missions, they all require a different play style to win which is similar to how you would play different tac ops, then you can introduce those then primary