If you copy Sea Dragon to a Titan, can the Titan make swoop attacks? The Sea Dragon keyword mentions “base”, which a Titan might not have (unless it would be considered where it touches the water for copying purposes).
In addition, if you copied Sea Dragon to a ship, would that then be considered a sea creature and not be able to have crew assigned to it?
The TL;DR answer to both is no.
These fall under a combination of the general Keywords vs. Shipwright rules and some of the more detailed bits that fell onto the second page of the Copy ability section. Copying a keyword doesn’t change a ship’s type, and the swoop attack part of the Sea Dragon keyword specifically refers to “a sea dragon” (as opposed to “this ship”), so it can only be used by a sea dragon.
Likewise, copying any of the various sea creature keywords onto a normal ship doesn’t make it a sea creature, so the “no crew” restriction will not apply.
You can still copy any of the sea creature keywords, but because they’re all worded specifically for their type they’re going be functionally useless on any other ship, including other (different) sea creatures.