Yes, some people use ether in glow fuel and even gasoline fuel for racing engines. Ether has a wide range of air fuel ratio at which it is ignitable so it will broaden the needle. It however can be used in very small percentages in glow or spark ignition before it starts causing detonation. In general I would not recommend it, unless you have a lot of experience with engines.

Acetone is not a substitute for nitromethane. Acetone appears to improve the tuning characteristics of glow engines when there is no nitro in the fuel. I have not tried it myself.