Maxxam Inc., Houston, has named John M....

Maxxam Inc., Houston, has named John M. Seidl, 51, president and John T. La Duc, 47, senior vice president and chief financial officer. Seidl will continue as chairman and CEO of Maxxam’s Kaiser Aluminum & Chemical Corp. subsidiary, and La Duc will continue as Kaiser vice president and CFO. Seidl succeeds William C. Leone, 66, who announced in March that he would retire in September, 1990. Leone will continue as a vice chairman. La Duc will succeed James V. Iaco Jr., who announced he will resign.