David can of course win U18, but a coach on the other side can get his player to lock David in backhand and also move him towards middle of the table for so playing out in his backhand. Players with topspin can also vary their speed and spin - using topspin with more spin than speed. David's attitude might also let him down. But gold should glimmer!
Carl - his footwork is not good enough, he has obviously not been practising footwork (sideways and dept) and irregular exercises. He can do well against "no-thinking"-players, but is so dependant on winning with his first forehand-loop from backhand-corner. Can loose against players with ability to place the ball and/or attack first.
Walter can be the big surprise of the tournament, but routine might be lacking to win! And unfortunately he has not been able to practise as much as he should due to school-work, but he is the player from TTTA with the best style. A weakness is a lack of pressure in the (good) loops, and that he might not believe 100 percent in himself (routine).
Nick has been having a terrible year with his health problems, and will struggle to get good results. He can surprise now and then, but good players should be able to utilise his problems in moving correct (due to change of playing-hands). Must be the boss of the table and not give them time to work on (or show) his problems. His loops are getting there, but..
Callum is coming strong, but it might be too short time for him to get his forehand-loop and footwork in good enough shape to get results. His backhand loop is outstanding, but is lacking in other areas. With a proper attitude he will do better and better during the tournament.
Eliza should be doing very well, but I feel it is so dependant of good coaching. She is lacking patience in her game, she is making mistakes herself when she should wait for the correct chance (and force opponent to make mistake). Her loop is not yet good enough (wrong balance and arm-movement) and she is often smashing in unbalance. Her defensive play is very good - so should stick to own game-plan!
Luke is very talented and has sharpened his game. Can get some very good result, but unfortunately too much is lacking. His footwork is not good enough and neither is his forehand-loop. Patient players can take away his game-plan totally. Luke is too dependant of controlling the game against speed - not everybody will give him speed to work on.
Sean has a deadly forehand loop, but no footwork. So he will have to win with his first loop from a good position - which good players (with a coach) will not allow him. Can get good results but can be really disappointed as well.
Edward has all the talent, but is not concentrating enough during coaching sessions. He should be winning U13 but not sure he will. Since he has been practicing more in a wrong way than correct then the wrong style might turn up. Balance totally wrong (as well as handgrip) - positioning and distance to table can let his good loops down. Good serves!
Aaron was improving very well before he got sick - starting to look like player, bending knees, leaning forwards and attacking with good loops. A large problem is that somebody seems to have giving him some wrong advice (coaching?) lately - he is trying to smash everything, loosing three times as many points as he is winning. In rhythm and after loops his smashes can work, but a coach can tell his player to "undress" Aaron - unfortunately. Makes me very sad/upset!
Olav can come as a big surprise. He might loose to other TTTA-players (me not coaching him at the table), but no U13 player should feel safe! He is improving rapidly now, following our coaching plan, and that can give unexpected results. He might of course also loose when he has the chance to win - he has only been playing for one and a half year and lack match-play against other players.

I do know very little about the other players in the tournament (almost nothing), so it is very hard to predict the final results.