What is your reason for earning status? Comp upgrades from coach to C+ or to FC on domestic/short haul international DL coach flights? Lounge access on international coach flights? If it's for comp DL metal upgrades, FB status won't really help you much as you will only be eligible for day of departure upgrades. If you want it for comp lounge Sky Club on international coach flights, FB Gold status will be better (DL no longer provides Sky Club to DL STE+ in international coach -- you now need to also be flying in a premium cabin (PE/FC) for access). Neither status will give you Sky Club access on domestic DL flights.

You can enter you FB number in Delta profile and select FB as program to credit if booking on delta.com. DL MQD earn when booking as partner coded flights is based on distance (whether partner or DL operated), not spend. If you fly 14K miles in business class booked as partner coded flights, you'd earn about 4200 MQD (30% of distance flown) no matter what you paid for your ticket.