1) The young guy must have been terrified, when grabbed and taken thru the anomaly?
Yes, so terrified he nearly passed out. Horrified might be a betetr word.
2) The pain of the grabbing him across the middle must have really hurt especially when it crushed his private parts in the tight black swim trunks?
It was excruciatingly painful. He felt he couldn't bear it, but of course, there was no choice.
3) When it swallows the lower body, I assume that the boys swim trunks will still be on the body and swallowed down whole or as near whole?
Yes, the trunks will be swallowed nearly whole.
The older guy
1) When the Tylosaurus grabs the older guy by the leg , near to where it joins the boy and shakes tearing the leg and genitals off .would the leg of the guys one piece swim suit still be attached to the leg or will it just get pulled out of the tight material ?
Since the monster grabbed the leg including the suit, part of it would tear off, too.
2) When it rips the guys body in two will that be across his middle , so that there is the upper body ,head and arms , and chest , will the tight black suit still be wrapped on the flesh ?
Yes, the sharp teeth will tear it, so parts remain on each section.
3) What all will the remaining lower part of the guys body consist off?
The lower part would be the abdomen, buttocks, and one leg.
1) How long would it have taking the Tylosaurus to fully eat the two guys?
Less than 30 minutes.
2) What will be happening in its stomach, how long will it take it to digest the two guys?
It is beleived the Tylosaurus was actually a reptile. The digestive juices would be similar to a crocodile's, and could digest bone and all. The softer body parts of course would be digested first. It would probably take 2 to 4 days to digest the meal.
3) What if anything will be left after digestion is complete.
The clothing, probbaly mangled and faded will be in the droppings. Nothing will be left of the actual bodies.