FOLEY UPDATE: The fate of House Speaker Thomas S. Foley (D-Wash.) seems to rise and fall with the Democrats' hopes for victory in the fall. . . . Several groups of dissident House members were meeting secretly to plot his ouster as Speaker, numbering among their complaints a general lack of political leadership and his failure to head off the House bank and post office scandals. But his opponents, who have yet to find an acceptable replacement, now fear that openly challenging him would undermine their party's chances of winning the White House.