Mayor Dobe is correct!

Left my robe and egressed, westbound
As an Estharian, he wore a robe, but presumably left it as he left Esthar. He went west over the transcontinental bridge.

Gathered courage, then, and left ground
Together with his comrades he founded FH, in the ocean.

Now host of tricks of greatest power
In his house, there is an Ultima draw point.

Host of the outcast and half a flower
Galbadia Garden's former headmaster, Martine, resides at Dobe's place after being shut out of GG. Dobe's wife is named Flo which is half the word 'flower'.

Your go, pyrefly maiden!