You can get a buck / boost transformer which will step down the voltage. What will be important is phase supply.
As the waffle maker is a totally resistive load there will be no problem using the different supply.
220 volt will use less energy.
If the motor is designed for 120V or 220V whatever the case, it will function properly.If it is a 12V motor and you supply 120V it will make a mess and you will probably get hurt from flying debris!
Not advisable, the voltage differential is too great.
It would involve some electronics work but it could be done. Might add that it could be more expensive than just buying the proper power supply. Use Use 220V 60hz motor to run 110V 50hz Generator.
of course. go to the market and buy a transformer. It will convert a 110V supply to a 220V supply.
nothing
If you have a transformer with an output adequate to run the motor, use it directly for the supply to the motor control circuitry. Remember when dealing with motors, the start current will be about 300% of the full load running amperage. Size the transformer accordingly.
Most 220 volt equipment will work on 208 volt supply. If the machine has a resistive load then the watts output will be lower than if supplied from a 220 volt source. If it is a motor load you will find that the equipment may run a bit slower but most motors will take the lower voltage. If the machine is a plug in device, install the appropriate receptacle to match the pin configuration and plug it in. If it is a hard wire installation this should be done by a qualified person.
At 20 amps the 220V will supply twice (2x) the power that the 110V will supply. The answer depends upon your meaning of the term 'better'. If you have a specific size load that you are supplying such as a motor that will accept either 220V or 110V then by using 220V you will have less of an impact from voltage drop and the conductor size will be smaller due to the current being 1/2 of the 110V. If by better you mean which one will give you the most power then the obvious answer is 220V.
Amp draw is always combined. 220V is uncertain if it is three phase or not, because there are both one phase and three phase applications of the 220V motor. In any case, the answer is always "combined".
No