Love all those bands, especially Chicago and Average White Band. But Tower of Power and Blood Sweat and Tears were good too.
I'd probably go:
Kooper on Keys
Prestia on Bass
Seraphine on Drums
Terry Kath on Guitar
Horn Section too hard to choose.
Vocalist too hard, but Hamish Stuart of AWB would be my # 1 choice. David Clayton Thomas would be # 2 and Cetera would be # 3.
My preferable songwriter would be Robert Lamm.
And AWB only had a few big hits (Pick Up the Pieces, Cut the Cake), but my favorite song is Queen of My Soul.