I like it. Yes it's long, but the names have meaning to the parents and that matters more. I probably would have left out one of the surnames for the sound (it has a decent flow as PEFNT or PEFND, but not PEFNTD) but again, that's something where the importance matters more. Poesy is a bit cutesy,
Emmeline is lovely, Fibonacci is wonderful (and if they can use a mathematician, I can get away with a physicist). Nautilus is not flattering but I like the reference.