Basic Animations:
Swimming: Layton moves his arms like he's doing the breast-stroke pull, while his legs drag beneath him.
About to Drown: Very similar to everyone else's, where both of his hands splash above the water with a very desperate expression on his face.
Drowning: He lowers his hat over his eyes with one of his hands, while the other arm and his legs float helplessly like other characters' drowning animation.
Aerial Attacks:
Neutral Aerial: I realized I never got to provide Layton's neutral air. I think one idea could be he pulls out a camera, grabs it by the strap, and swings it around himself. The swing effect would look a lot like Marth's neutral air, except instead of the sword, it's a camera pulling it off.
Up Aerial: He claps both of his hands above him. Yeah, this might sound random, but the down aerial idea I previously provided is another random-esque move, so I see his up and down aerials being similar in this regard.
Specials:
Up Special - Custom Glider: I finally figured out custom versions that could work for this attack. The speedy version of this attack would be his Fossil Glider that he used in Azran Legacy. The Fossil Glider would work a lot like Pit and Dark Pit's up specials, except the main difference here is that the glider flies farther and doesn't render helplessness. The power version would be Layton grabbing on to a propeller device with one hand (while using the other hand to grab his hat of course) and using it to fly upwards. The propeller would look very similar to the one Don Paolo attached to the Layton mobile in Unwound Future, but it would be bit smaller. The propeller flies slightly less farther than the other two versions, and it can damage foes in a way like Link's up-special. It would be attached to a metallic pipe, and Layton releases himself from the glider like the other two versions.
I got the idea of the differing up special moves from Megaman's up special variations: they are not just limited to Rush. They can vary thanks to different gadgets: either Rush (Normal), Beat (Speed), or a fan (Power). Similarly, Layton's up special would not be limited to the Custom Glider. One could customize it to be the Custom Glider (Normal), Fossil Glider (Speed), or a propeller (Power).
Taunts:
Side Taunt: Layton puts one arm on his chin, and his elbow rests on his other arm. He then moves both of his arms outward like he's explaining something and says "Ah, wonderful!" His words for this taunt would be used in Smash World when a mii picks him up while traveling across a board.
Victory Animations:
Normal Victory Animation 2: Still stays true to my original idea, but instead, he says, "The real winner of this battle... was you!"