1- Tank PT for last form shouldn't be very different from what it is for previous forms. Couple of PLDs mages/bards/corsairs. Any logical tank PT will work (PLD PLD RDM WHM BRD). Can replace a bard with a corsair or second paladin with a corsair if you are fast enough to replace the PLD should he/she die. Other 2 pts should be focused on damaging PW
2- You can tank PW with skilled mages and good paladins, IMO. PLDs and mages should all have proper medicines to erase ailments as quickly as possible (echos, holy waters, RR, remedies). Aegis PLDs shine on PW since it has built in instant-cast (no time to swap equip to an mdb setting). You can still get unlucky with curse>GAIII so having backup tanks on standby is essential. PW cannot be tanked while the lamps are alive however since they will assist PW and no tank can deal with all the lamps and PW. Therefore, your goal should be to eliminate the lamps and then drop PWs health as fast as possible.
3 - Rangers and summoners are ideal DDs since they can avoid all of PWs TP and GA moves/spells. However, the rangers need to be smart about their hate and attack from places where they won't MPK your ally if they do pull hate. Other DDs can work as well as long as they time their attacks/WSs correctly. IE, weapon skill after it uses a big spell. People are going to die, it's unavoidable, but everyone should have RR so you don't waste your mage's MP.
4 - As far as I know, you cannot kite PWs lamps because they have a very awkward shared hate system with PW that I still don't completely understand (VS might be able to explain it). The only thing you can do is move the people w/o any hate far far away and let the people with hate force it to AF, die, RR and get back to work. You could log some people off but then someone could get angry and make some journal posts and call GMs on other servers
.
The design of the final form of PW is pretty terrible, IMO, but we have to deal with it for now [so are the drops, mostly
]. The fight is a race more or less, you need to rip through the first forms as fast as you possibly can so that you have lots of time in the final form. Ideally, you'll want an hour left to kill the last form from what I have seen thus far. Hope this helped you ~