The Taranis uses the FrSky protocols where as FlySky use FlySky protocols. They will not be able to talk to each other (JR modules excluded. I've no experience with these)
Long story short; no, the QX7 will not be able to talk to the FS iA6B.
PPM refers to how the receiver talks to the flight controller, so despite FrSky and FlySky receivers being able to talk PPM, the transmitters are not interchangeable.
When you're looking at receivers, make sure they're either FrSky, or FrSky compatible. That way you'll be safe with the Taranis.