Are we talking about the full +2 CR Vampire template or the lesser Vampire Spawn effect?
Vampire: Type changes to undead, gain darkvision 60ft, gain +6 natural armor, CHA used for bonus hp instead of CON, Channel resistance +4, DR 10/magic and silver, fast healing 5, cold and electricity resistance 10. They can also turn into mist, a wolf, or a dire bat. They cause energy drain with slam attacks. Constant spider climb. Dominate with a look. The can also suck blood.
Undead in general also get immunity to mind effecting spells and abilities, bleed, death effects, disease, paralysis, poison, sleep effects, stunning, ability drain, physical ability damage, energy drain, nonlethal damage, exhaustion, fatigue, fortitude save based effects (unless they also work on objects).
Weaknesses are damaged by positive energy. They can be repelled with garlic, mirrors and holy symbols nor can they enter homes uninvited. Running water and sunlight can destroy them. Stakes can incapacitate them. Incapacitated at zero HP, requires a coffin, cannot act in day light.
The Vampire Spawn gains the blood drain, dominate, channel resistance +2, DR 5/silver, resist cold and electricty 10, fast healing 2, gaseous form, shadowless, and spider climb. It also gets all the weaknesses.
Either way you cut it, there's a pile of power in these templates. Of course, there are bad things too, but I'd say what they gain outweighs most of it.
The problem is coming up with something on the divine side that can even come close. The immunity list alone is staggering.
Here are some ideas:
Demon Possessed but changed to use angels in sort of a "divine host" concept. You'd have to break it down to be a reasonable list of abilities for whichever divine creature inhabits the character, but it is a good basis.
Fey could work, kind of a "avatar of the living world" concept. The earth itself is powering the characters in their effort to prevent the death of all things.
Genie-Bound though obviously you'd change it from genie to the appropriate god/goddess or representative.
Half-Fiend but switched to half-divine with the appropriate resistances/smites/dr modifications.
Divine Guardian sounds pretty heavy but may need a little something more since it rates only a +1.
And lastly, if the druid doesn't want to be a vampire, he can always be a Siabrae!
Do you want your players to become vampires?
I dont think you even offer it I think you should give them sometype of custom item that is really really good almost mythic instead of Vampirism
Unless Luvick's also agreeing to make any converts immediately free-willed, accepting his offer would be an astonishingly bad idea.
The giant pile of powers is kind of cool, but dying in sunlight, and being another guy's slave until he releases you or actually die, is kind of a bummer.
Make sure your player understands what vampirism entails before they accept it.
(Oh, and becoming vampires can have the hilarious repercussion of them being vulnerable to command undead and other effects. They're going to be running off to attack the high temple of Urgathoa soon, and they'd be in real danger of becoming pets if they show up as vampires).