Doubt on the relationship between the sensitivity and the complementary sensitivity function
You already have the answer $S+T = 1$, the relation must hold true at all frequencies.

Therefore if your sensitivity function $S$ has a high-pass characterisitic, the complementary sensitivity function $T$ will have low-pass characteristic. 

As for bandwidth, your curves make sense. The red sensitivity function has a larger bandwidth than the green sensitivity function. Therefore, the red complementary sensivitity function has a smaller bandwidth than the green complementary sensitivity function.