They can submerge their body, yes! But not fully. They’re able to submerge until the water gets close to their main vent (which is in their chest area). If too much water gets in there, their engine drowns and they’ll suffer malfunctions and/or sink.

The ships can operate slightly submerged or hover a few meters above waterlevel, as if they were skating above water. They can’t fly! Just hover and glide a little bit above water.

Have Concordia as an example (the black triangle in her chest is where her main vent is located):

Some ships actually get slightly harder to pilot if you submerge them too much, mainly if they’re in a stormy sea. 

Conte di Savoia, for example, was built with a system that helps her stabilize herself with more ease in rowdy seas.

The ships that can submerge themselves almost fully are the Submarine Aircraft Carriers!

I really love the phrasing of “activities and enrichment,” as though they’re zoo animals that you need to keep physically and mentally stimulated, and not primordial beings 😂

Your major obstacle: Harry Potter erotica.

Your current challenge: A salty surprise.

The hidden factors you need to know affecting your current situation: A homoerotic volleyball montage.

New ideas, people, or things that can help you grow further: An AR-15 assault rifle.

Interesting question! Before I get into that, let’s look at the three we have (for some reason, Fu’s doesn’t change even when Wayzz isn’t in it? ok): Tikki’s become like shiny hematite, Plagg’s becomes a solid silver ring. And, as you noted, Hawk Moth’s is a lil locket/pendant. 

Yeah I’m fine lol