This is a pretty tough one. Dorothy is really hax and hard to deal with, and she could "probably" beat Fuegoleon in her Dream World.
In the Fana fight i pointed out that like any other elf possessed, Dorothy's range and power of magic was most likely amplified. While in the Dream World regular Dorothy's power might rival her elf counterpart, but i dont think regular Dorothy has the same reach and casting speed outside the Dream World to pull someone into it like elf Dorothy. And question is also how long she can maintain that with her regular power, but thats mostly just pure speculation.
I think that Fuegoleon with Salamander has that overwhelming firepower and magic power needed to beat someone like Dorothy. He is faster and with Salamander he became a long range nuker. Dorothy could (maybe) absorb his nukes, but here comes the previous speculation of whether she can counter/block/absorb the entire nuke/nukes with her regular spell range and casting speed.
Dorothy is hax, but i think i'll give it to Fuegy. For now