what should i use to wire this bathroom?
You'll need at least one 20 ampere circuit to supply the bathroom receptacles, which cannot serve any other rooms. 

You cannot use 14 AWG conductors anywhere on a 20 ampere circuit, all the conductors must be 12 AWG or larger. 

The likely course is to have one GFCI protected 20 ampere circuit to serve the bathroom receptacles.  One 15 or 20 ampere circuit to supply the lighting in the bathroom (this will include the exhaust fan).  And one 15 or 20 ampere circuit to supply the refrigerator.  Later when you want to add the microwave, you can install another 15 ampere circuit to supply it.