TBH, I think FPM takes this, if only barely. FPM's acrobatics can likely match Chelsia's movements without a problem, he has more range with his projectiles and, even if he runs out of it, he can also just reflect Chelsia's own projectiles without a problem. FPM has a melee range advantage with his pen/pencil, has a higher LS, while also having his own dash attack, as well as AP based statistics amplifications. FPM technically has a bigger AP, but it is so close it barely matters, but it is still worth mentioning
Overall, I think it is quite close, but FPM just seems to match or exceed Chelsia in almost every regard, his Acrobatics and mobility are not exactly too far behind Chelsia's, combined with his extra range (Both ranged and melee), attack reflection, higher LS and a tiny AP advantage would give him the edge imo
