i just did this blm/nin rdm/nin and I have to say the mobs get in the way alot.the vahzle nm was easily dot->zoned, and i used rdm/nin. it's pretty rare that the mobs near the zone got in the way, but even if they did, you could sleep them, dot the nm, and zone.
what we did was freeze sleep which took off 10% then gravity kited it while doing tier II nukes till we got low on mp then bio II and zoned. The rdm then focused on clearing any mobs that will aggro while kiting back. The blm then bio IIs the NM runs to zone. I then rest 1 tick to make sure the NM wouldn't aggro me as I zoned with no shadows. You should be able to catch up to it with 15 or so seconds left on bio. when we got it to ~10% blm es sleep II and cast freeze to kill it.
burn and poison land but don't last very long bio II takes off aprox. 2%
it also has a move that gives it a ton of shadows so you need someone to -aga while the other puts bio back on before it regens.
blm/nin can possible solo this since you can rest a tick in full lvl 75 gear every bio cast but avoiding aggro would be rough and clearing its shadows could get bad if sleepga doesn't land