Everything has been answered satisfactorily already just a couple of details;
15 hours of mandatory training
There is NO training requirement but teh 3 hrs for a check ride sign off; however it
generally takes about 15 hrs (10 flights or so) to get somebody with a "fresh" European IR proficient to pass a IR cehckride in teh US.
Not because they can't fly Instruments but to:
- get familiar with local airports
- get familiar with the approaches likely to be flown
- get proficient in GPS approaches (if the aircraft has an IFR approved GPS)
- get familiar with radio communications and local procedures
The three hours training for CPL and the three hours for IR with an FAA CFII and then sit the two check rides with a DPE
Very unlikely; the FAA CPL SE consists of manuevers which are not flown in Europa-land, neither for the PPL nor for the CPL.
To gain proficiency in these maneuvers will take at the very least 6-8 hrs (4-6 flights) On top of that the applicant needs to meet the requirements of 61.129 which have recently changed. Ten hours of Instrument training is now required but that can be completed simulataneously with the average 15 hrs of instrument training.
Dual day and dual night cross countries need to be completed with an FAA authorized instructor (read an FAA certificated instructor) for another 2 hrs each.
In total you need to expect about 15 hrs for the IR and another 15 hrs for the CPL SE.