Defense Secretary Caspar W. Weinberger and Commerce Secretary Malcolm Baldrige have joined forces to fight the sale of Fairchild Semiconductor Corp. to a Japanese company, Pentagon officials said . . . Ford Motor Co. has decided to offer buyers of its popular Taurus and Sable models a choice of low loan rates ranging from 3.9% for 24 months to 9.9% for 60 months or a $400 rebate . . . An investment group led by Asher B. Edelman reduced its holding in Lucky Stores to 4.8% to comply with a standstill agreement.