I can see signing this guy as an alternative to Caicedo - they look quite similar in their strengths and weakness. That said, I don't think Lavia has any superstar standout qualities, whereas Caicedo's ball-winning ability is cheat code levels of good.
In both cases, I don't see either player being considered as 6's in this team (not that they couldn't do a job there). They're not smart enough footballers for the role as Arteta invisages it, imo. They are both very good because they are extremely athletic and techncially sound. Neither are elite in their defensive positioning imo (though Caiceido is very good), nor do they see the way play is going to develop - both on and off the ball - before it happens in the way some elite 6s can.
Rice, by contrast, has other worldly defensive anticipation skills. He doesn't quite have their level of athleticism, but his ball-winning is still up there with the best because his positioning and tackling technique is so good. I wouldn't argue that he has shown a level in his progressive passing that Caicedo/Lavia hasn't, but I think he is the much smarter footballer generally and that makes him more coachable and likely to learn how to find the right risk/reward approach to his passing game that is required in the role front of the back 4 (at least in the way I think Arteta sees it).
Partey, for me, good as he is on his day, never quite got it because he's just jot a very smart footballer. He can play every pass in the book, but he doesn't see patterns and too often doesn't use what he has efficiently. And I see Caicedo/Lavia in that same way - and I'm pretty confident Arteta will too.
I think Arteta has his 5-5 (5 players attacking ahead of the ball, and 5 defending behind it) in mind again, as we saw last season, but with more flexibility and variation and less predictability in the way we attempt to isolate and create overloads. And crucially more athleticism and ball-winning ability in the 5-man unit that stays mostly behind the ball.
I think this will be the defensive core that won't really change if we can help it:
‐ - - - - - Rice
Then, we'll sometimes see: 1) A Caicedo/Lavia slot in next to Rice but from a starting position at RB, or Zinchenko from LB - with Kiwior/White as the 3rd CB. In some games, when we really want to put it on an opponent, we might even see: 2)Both Zinchenko and Caicedo/Lavia next to Rice at the same time with a starting position of LB and RB respectively. In other games we might go more conservative with: 3)Zinchenko/Caiceo/Lavia starting in midfield alongside Rice, and two defenders in at FB.
1.
‐ - - - - - Rice - Caicedo
Kiwior - - Gabriel - - Saliba
Or:
‐ - - - - Zinchenko - Rice
Gabriel - - Saliba - - White
Or:
2.
Zinchenko - Rice - Caicedo
Or:
3.
‐ - - - - - - - Rice - - Caicedo
Zinchenko - Gabriel - Saliba - White
If it works out that we sign both Rice and Caicedo, adding them to Saliba and Gabriel will take us up levels from last season in our ability to defend transitions. Which given how much of the ball we have is not only the type of defending we do most of the time, but along with set-pieces, the main way we gave up chances and goals last season.
Rice and Caicedo are absolute monsters in transition. They'd jump all over any attempt from opponent's to break out from our pressure. We'd absolutely swarm teams for long periods of every match. And when they do break out of the octopus-like grip we'd put them in, those two would eat most attackers alive in any break away. And that's before you get to the three 6'3+, super fast and athletic CBs.
