If it were up to me, i would rather than evolve the boat ride to a more sensory based experience....ALIEN encounter meets Popeyes meets Jungle Cruise.
His goal in the first movie entirely was to destroy the team until he fell in love with Kay, then his goal was to do what it takes to kidnap her and take it to the lair.
Second movie also involves Gillman in Florida trying to kidnap a girl. So why not create that feeling and vibe inside an attraction. And also why not expand the concept to include monsters from the regions.
So if I was UC, the concept would be an indoor boat ride with rapids and a sensory based restraint that invokes sounds, smell, and touch. Humaniod remains with aquatic features were discovered by Dr Frankenstein's great great great grand daughter and you are part of the expedition team to discover them but it won't be an easy journey as you will be traveling through an expedition through the Carribean, Central America and South America to find him. Due to the roughness of the journey, our boat has been fitted with harnesses to keep us safe as we will be traveling fast through turbelent waters and seas. (these harnesses hold the tech for the smells, sounds, and touch).
While on your expedition, you experience rapids and storms as for face the following: La Luscha (Carribean Monster) El Encantado (Brazilian Legend), El Caleuche (Famous Chilean Story about a ghost Ship)....adding these legends add to the ambiance and expands the ride story so you feel like you actually traveled. (Pirates of the Caribbean Shanghai meets Popeyes is the feel here.)
Once you reach the black Lagoon on a dark night things are calm but in the distant you see the creature and he is staring at the boat looking for one of the guests for he/she/it has fallen in love. We hear movement in the water but we can't see it aside from a light glow. The boat rocks gently almost as if someone was climbing aboard. Wet footsteps can be heard, then through randomization, a few people on the boat start feeling a slightly wet claw on their shoulders and a weird growl in their ears. We hear footsteps but we can't see the creature as he moves. We smell the light stink of seaweed get stronger as he gets closer to you and then from a cloud the moon comes out and there is a creature AA on the boat up close. He attacks, he lunges as the cloud blacks out the moon. We feel him touch us and move through the boat through the harness and other sensory tools. Our captain tries to protect us and we are left to our senses about what happened as we just hear gunfire/ flashes of lights from the gunfire and feel water "blood" hit us. We hear a splash in the lagoon and see a figure swim off in the distance as the sun begins to rise.
As the sun rises, we see the aftermath. There small trail of blood. from the inside of our boat leading to the edge. We travel back to our launch location with a fear in our hearts about what happened in the black lagoon.