Presenting U.S. District Judge Rebecca R. Pallmeyer with an intricate choice-of-law puzzle under Article 9 of the Uniform Commercial Code, Cozen O’Connor P.C. relied on the common fund doctrine, plus its contingency fee contract with a Philadelphia firm, Michael R. Needle P.C., in seeking payment for representing Needle, referred to as MRNPC, in an interpleader case that resolved disputes about allocation of settlement …