REFLECT
I would make it more like Liement, a 10 second buff that annuls the first offensive magic spell but instead of healing the RDM it inflicts the same amount of damage on the target.
MINI
Attack&Defense, sure. But character models can't shrink in FFXI, only be replaced. (THis would break lock, interrupt casting, etc). So I'd say no to that last bit.
TOAD
Again, model changes are bad.
STOP
Too similar to break. Instead, make it a debuff that negates and blocks any and all haste and slow effects, including those gained from gear, traits or spells. (Dual Wield and Martial Arts excluded.)
DEATH
Great for pesky links, however it would make it more of a utility spell with normal cast, recast and success rate. The target essentially despawns rather then dies, as if pulled out of it's area and unagrod. This ensures it respawns shortly after with no rewards whatsoever.
FOG
Could just call it Amnesia, and like gravity would only work on regular mobs.
A line of spells that I have rarely seen anyone suggest are Negaters. Like Banish on undead negating Damage Taken-, RDM could get a line of spells that does just that on other stats on other monsters, but only if there is something to negate. Things like Physical/Magic Damage Taken, Double/Triple/Quadruple Attack, Fast Cast, etc. Only one of these could be active of a mob. (The Stop suggestion above would be such a Negater.)