The elf question: That depends on you. There are advantages to both, but the extra 20 mana is very valuable to me. Therefore, I chose elf.
The parry question: Again, that depends on your style. I wouldn't go without it. Duku does quite well without it.
Stats depends on your weaponry. If you only use a high speed, high swing speed weapon like soul seeker, then you don't need a lot of dex. If you want to use the ornate axes effectively, then you need at least 150 stamina, if not more, and that means as much dex as you can get in addition to stamina boosting items.
You only need enough intelligence to get the specials off. If you can work a little bit more intelligence in there, then repeat-casting (or chaining) specials can be very worth while. I would suggest 30-40 int.
That leaves the rest of your stats in strength. Depending on what armor you use, you may not need to go all the way to 100 strength if you PvM. My non vampire samurai has less than 100 str and he does fine. My vampire samurai has less than 150 stamina (about 120 after bonusses) and he does well with a high SSI diamond mace with mana leech or wind's edge.
Stats, however, are very easy to manipulate once you're skill capped simply mark a capped skill to up (I use tactics) and the stats fly to wherever you want within a couple of minutes. So go with what feels right and adjust until it feels better.
Anyhow, the simplest version of pro's and con's of sampire:
Pro:
Life leech with EVERY hit
Poison resistance
Con:
Need a whole lot of fire resist
Can't use cure poisons
The cons are easily counterable. You can simply ignore the poisons that aren't resistable, as you'll leech more life than the poison does damage. And the fire resist is easily aquired through better armor/jewelery.
The parry question: Again, that depends on your style. I wouldn't go without it. Duku does quite well without it.
Stats depends on your weaponry. If you only use a high speed, high swing speed weapon like soul seeker, then you don't need a lot of dex. If you want to use the ornate axes effectively, then you need at least 150 stamina, if not more, and that means as much dex as you can get in addition to stamina boosting items.
You only need enough intelligence to get the specials off. If you can work a little bit more intelligence in there, then repeat-casting (or chaining) specials can be very worth while. I would suggest 30-40 int.
That leaves the rest of your stats in strength. Depending on what armor you use, you may not need to go all the way to 100 strength if you PvM. My non vampire samurai has less than 100 str and he does fine. My vampire samurai has less than 150 stamina (about 120 after bonusses) and he does well with a high SSI diamond mace with mana leech or wind's edge.
Stats, however, are very easy to manipulate once you're skill capped simply mark a capped skill to up (I use tactics) and the stats fly to wherever you want within a couple of minutes. So go with what feels right and adjust until it feels better.
Anyhow, the simplest version of pro's and con's of sampire:
Pro:
Life leech with EVERY hit
Poison resistance
Con:
Need a whole lot of fire resist
Can't use cure poisons
The cons are easily counterable. You can simply ignore the poisons that aren't resistable, as you'll leech more life than the poison does damage. And the fire resist is easily aquired through better armor/jewelery.
I deffinatly did not do horrible. I went in, Honored, EoO, and chugged a dex potion, and it was on. DH hit me often and I wasnt leaching too much with my ornate early on. A few swings later, (Achived Perfection) I was keeping my health around 40-80% and was doing fairly well. I was mana drained practically the whole time. I got her down to about 2/3 health and then it happened: i missed twice in a row, lost perfection, mana drained..not good. Then i died...But! I can do it! I know I can. I think next time im going to try the SS or my Katana, my Ornate worked well, just curious how the others will do. 
In fact it was from a vendor shop right outside Destard/Tram.