you'd think the world's best navies would Know that if you shoot with cannons at targets underwater, you''ll do fuck all. they should have waited for the titans to emerge from the water, and Then they would have been easy pickings.
Historia's definitely having Eren's kid. Then he did memory altering. Eren's just concerned with Mikasa, because unfortunately, his love for her isn't romantic, and he'd hate to break her heart. That's why he kept shoving the Ackerman loyalty/master thingy down her throat, so she won't think it's love...