Fireworks decoration?

[Primes]

Is is possible to find these on White Beast C? And if it is, whats the right mapset to run into Jaggos?

[EspioKaos]

Yes; Fireworks is a special drop of the Jaggo Acte, so it can be found at any level. For the spawn chart, see this article: http://psupedia.info/White_Beast#Enemy_spawn_chart