Yes, quality fast rolling tires will save you power compared to your current tires and that should result in faster speed.
Yes, lighter wheels that are also aero will save you weight and reduce drag compared to your current wheels and that should result in faster speed.
Yes, of the 2, quality fast rolling tires will likely net you a bigger gain overall and also when cost is considered.
I dont think a Conti GP5k tire will, in and of itself, flat more frequently than your tires. It rolls fast and has puncture tech.
Additionally, if you just convert the wheels to tubeless, you really dont have to worry about most common flat scenarios.
As for how much faster you will be?...
