One Relay or Two

I finally managed to blow up the diagram, and while blurry, it appears that the left "low speed" motor is actually two speeds, low and high

The right hand relay (low speed) evidently runs only the low speed motor on low

The left hand relay (high speed) evidently runs the low speed motor on high speed as well as powering up the high speed motor.

So I'd say that if high speed is all you need, and IF YOU have a relay large enough to handle the current, one relay is all you need.