I think this is the best chapter so far.
But since destroying the Dragon Tooth will restore the time line, technically, Marle, Lucca, and Robo should loose all the experience they got. Since the inventory is shared, I guess there is no way to avoid that paradox with the items.
And, before that, once did their many past versions of them appeared in this time line thanks to TTI, it's a miracle their time before TB didn't affected anything further, though wierd considering how the Reptites have not record of humans after 1 AD, unless since this is a new time line not even TTI was able to make them appear, though it wouldn't explain the Cyborg appearing then.
I'm thinking too much into it, better just watch it, and think about it later.