I'm pretty sure (and DDO Wiki says this as well) that Vampirism is positive-typed, so it won't work in an undead form.
There are a lot of mobs that use light damage. From Wights in Delera's (and possibly even earlier, I wouldn't be surprised to see light damage in STK on Elite) to Trogs and Gnolls in Vale and beyond, pretty much any divine creature save a handful has at least one light spell, and a handful of bosses will use Divine Punishment, as well. You don't really notice unless you're a PM, as the damage from those is generally fairly small compared to, say, Disintegrate... until it's dice are increased due to the target being undead and then multiplied by 4 and you have no good way to reduce it. You can avoid most of them with Evasion (for Sunburst) or by strafing the rays, but getting hit by two of them in sequence in Vampire form will probably (almost) kill you outright unless you're really tanky or you're playing solo on Normal.
The best way to find out how bad light damage can be would be to simply play as a PM. It can be pretty brutal at times, but that's the price you pay for the benefits of being undead. I'd never play as a Vampire, though, as quadruple damage makes light damage too dangerous in my opinion. You can deal with two or three hits at double damage by hiding or whatnot, but there's just not enough room for error at quadruple damage for my tastes.
Im using only wright or lich form with death aura, it usually heals me 60-90hp per 2s. also NEburst is nice when you need quick heal - it can do 150-200hp.
hope it was helpfull to you
Light damage is a pain in form. Running with devils and drow priestesses are tough for an undead toon. You'll be fine in the rest of the quests.
Aye, I know. Fortunately I Have upgraded Circle of Hatred - thats 5 Harms per rest, so I should be fine with stat damage restoration.
Also, I w?ll try Vampire form, if that w?ll not work, i can always switch to wraith.
Last question I would love to get an answer to is: out of those 4 handwraps I mentioned, which ones are general?y the best?
Antipode/Graves/Ivys are very good handwraps. I use all in my monk. I change depending on the enemies I fight. I love Graves so much (level drain is very good for trash), but all are useful. Vampirism (Ivy) is awesome with a good healing amplification; I use this wraps when I need self-healing (not hireling). But my monk is not undead (Pure monk, I have a pale master, a pale trapper and a pure monk); perhaps Graves will be more useful for you.
Alchemical hadwraps are a great help also, and the best boss beater for (not shintao) monk (I think)
I think is matter of preference and the tinket you love use. And I love Graves for level drain and soul eater, but if your enemy is level drain immune then antipode wins. For bosses, alchemical or antipode. Different enemy, different weapon. Monk is not different to other warriors in this. Use both handwraps and make one alchemical ;)
And Antipode is awesome with a Planar Focus Prowess. I think high tier antipode with planar focus prowess will be more useful for you.
Regarding the harm question, it does heal stat damage while in undead form. The complaints about it not working in that recent thread were because there is no longer any way to acquire harm scrolls. You used to be able to talk to the vampire collector from House J while in undead form and he'd call a weep for you, and the weep would occasionally give you a harm scroll if you dumped all your collectables on him. Something like a half dozen harm scrolls per 100 turn-ins. So it really wasn't viable, but even that was removed from the game. Circle of hatred is now the only option, but since you already have that you should be pretty set on that front.
I would bet money that the vampirism weapon effect does NOT give hp back while in undead form.
Regarding light damage, pretty much all "squad based" mobs deal light damage. Any mobs where there are melee, arcanes and divines (eg: hobgoblins, duergar, drow, etc...) the divines can and do cast light spells at you. That's a healthy majority of quests. The reason that drow priestesses and eladrin from RWTD are known is because they do a huge amount of light damage. Eladrin hit for 120 on everyone, meaning 480 per shot in vampire form. The average hobgoblin cleric in gianthold probably only hits for like 30 so nobody notices them, but in vampire form you'll definitely notice the 120 hp light blast.
Whatever you do, don't try to solo zerg Relic of a Sovereign Past on elite in vampire form. Those duergar divines spam light like it's going out of style. I'd say quests where there isn't light damage are the notable ones, not the other way around.
Yes, vampire shroud is a trap. Wraith is waaay more useful. With wraith light damage is only very dangerous in a few quests. In vampire form light damage is dangerous in a lot of quests.