Waffennacht wrote: »

I don't recall the dawnguard performing any kind of "test," to see if the hero is a vamp/whowolf lore wise....

So I mean a sneaky undead may get into their ranks...

And who doesn't love Blade?

You didn't get far enough then; Isran casts a spell later in the questline and turns you away if you're a vampire until you get cured.

(Though for some reason he doesn't perform this test when you join initially, which would have been a logical time to do it.)

godagarah5000 wrote: »

it gona be a possiblility? id love to see vampire lords running around and werewolf players as members of the dawnguard

With any luck, no.
I don;t recall a date given for the formation of the dawnguard outside of Era, and the Volkihar Bloodline is unobtainable lorewise as the coven is entirely secluded for a long period of time (as learned in Skyrim).