No Amiga BlueTooth support, sorry. The Poseidon driver is only enough to recognize a dongle - there's no stack to drive it. It's like having a SANA-II driver for your network card but no Miami/AmiTCP/whatever to get online.
I don't know anything about this FPGA Arcade board, but if it uses BlueTooth to emulate an Amiga mouse (like Minimig does for PS/2 ports), then it could work. But there's no support on the AmigaOS side of things.