The C-Max is just a Focus with a different body. Most repair procedures and upgrades are the same for a C-Max as a Focus (in your case Focus Mk3). Lots of spares will be interchangeable as well. Suspension components may be slightly different though due to the taller and probably heavier C-Max.
No reason why not. If it would fit on the same engine in the Focus it should fit in a CMax.
I guess you have the 105Hp 1.6 Duratec and want to fit a throttle body off a 150Hp Ecoboost? I do not know how similar these engines are and if the parts are compatible but if Focus owners have done it then you should be good in the CMax.
Edit: It looks like the Focus had a 125 version of that engine. Dont see why it would not fit although I doubt it will make a difference to the power.
Here is a link to the 2012/2013 ish C Max - Engine choices are near the end. Here is a link to similar Focus brochure. Engine choices also near the end.
You should be able to find your engine code on your V5 under engine number or variant. If not there it will be on the VIN plate or on the engine somewhere.
Google says the 1.6 Duratec is a Sigma engine. The Zetec was an earlier version of the Sigma. These engines are totally different to the higher powered Ecoboosts.