Yup the middle bit looks like a stinkie, a Bayliner or summink. Nice conversion!
Those slides are available as bolt-on accessories for flybridge pwerboats
In general, I think selling a large power boat and buying a massive cat, and maybe getting an exp sailor to look after it in the caribee when you can't use it, is a damned good idea
Its only a tri if the centre hull is in the water all the time, which it looks like this one isnt. Otherwise it is a catamaran with a centre pod (like the Prouts).
That's not a slide but a jet propulsion unit....once the Honda 4 get's it on the plane the jet unit takes over and pushes it along at 55 knots. You too could enjoy this type of sailing if you moved to Florida!!