(1) Are eliminated units removed definitely from the game or can they be used for future reinforcements ?
Yes for the Filipinos. No for the US (except for arty and cav, see 7.0, 4th dot)
(2) When a leader is alone in a zone after a defeat, and if he survived, he is moved to the closest area containing a friendly force. Can this movement be by sea if there is no other solution ? [/q]
Well. Let's say yes.