Can someone explain how Luffy is grabbing Ulti from behind when he jumps into her from the front?
He jumps past her, grabs her on his way and then throws her.
But, to be honest, the choreography of this fight was… a choice. For it to make sense, we need to consider Luffy made a lot of twisting and some movements in the air that he shouldn't be able to do.
Like, regarding their positions it starts like this: P1... Ulti... Luffy.
Then Luffy jumps past Ulti, grab her by her horns and throws her in front of him. That means she should land between P1 and Luffy. But on the next page we see Luffy is between them, like if he twisted his body 180º while he was doing the throw. Also we can see he is in the ground already on the panel when he is throwing her, but on the following panel (the one he is weirdly between the two enemies) he is mid-air.
Then P1 tries to bite him, Luffy grabs something on the ceiling to pull himself away from P1's attack and instead of attacking P1 from above he somehow uses soru to appear under P1 and attack him. Not just very weird choice of movement (unless he knew P1 was going to dodge his attack from his initial position), but also kinda impossible since Luffy would need to know Geppou to be able to soru mid-air (or he can now bounce in the air in his base form like in G4?).
It was clunky.
FUTURE VISION EDIT:
Oda is updating his manga based on real-life discovery. Check out Spinosaurus 2020, a swimming dino.
It was already cool enough to see him changing to a more accurate depiction, but finding out it is a recent discovery from like 2 months ago just makes it a lot better.