firstly id spray the calipers black or silver personally, think those colours look best personally, but thats up to you aint it.
I did mine on my last car whilst on the car, i used black smooth hammerite and a small paint brush and just cleaned them with water and a stiff brush to get any dirt or mud off, then dried and then painted straight on, i wasnt being fussy about it so you may want to add primer etc to make it last longer, but to be honest mine was ok.
With the alloys if they need cleaning get some of this stuff
http://www.cleanyourcar.co.uk/wheels-amp-tyres/premium-blue-rim-wheel-cleaner/prod_190.html its awesome, gets all the brake dust etc off and is safe on all wheel types(if you get it ill tell you how to use it).
Then if you want to protect them you can use normal car wax as you say, do that if you already have some, if you dont and want to use something then get some of this
http://www.cleanyourcar.co.uk/wheels-amp-tyres/poorboys-wheel-sealant/prod_9.html its all good stuff on that site. All that will do is make a barrier so that brake dust doesnt cake its self on, and you'll only ever need water and a brush to clean, rather than alloy cleaner.
By the way are you going to be doing all this yourself? no disrespect i think its great girls getting stuck into their cars
