First question, is the $15 million budget firm?
Reason I asked, is that there are at least three Falcon 900EXs on the market today under 20 million USD;
Serial number 025, asking 16.950 USD
Serial number 031, asking
14.500 USD
Serial number 048, asking 15.500 USD
You might check into these aircraft, not only will a 900EX meet all of your requirements, but will greatly exceed them.
Go to this link for more information on the above aircraft.
Jets For Sale