Hmm, Vampire Anna reminded me a lot of Creature of the Nightlight. Good call saying she had only been turned a few weeks back.
As a one-shot, this is just a teaser. It really did feel like it needs a follow-up, but if you did, then the first chapter moves too fast (Elsa taking an immediate liking to Anna). I'd say split the difference, and make it a three chapter story! That way we get to see Anna reciprocate feelings and Elsa kick Han's ass....Yay!
Anna just has that likable personality. How could Elsa not take an immediate liking to her? Plus maybe Elsa is just lonely. :(
He he, all of that sounds like a great idea xD I might consider continuing it at some point, but other things have priority. Hans' getting an ass kicking is certainly needed more in this fandom!