I was afraid your OC was going to end up a Mary Sue, but it looks like that wasn't the case since she didn't go around solving every problem. I like Dawn taking the lead and getting things done, but shouldn't she be an adult and just talk to her sister about Spike being alive? Isn't it a big problem when other people make Buffy's decisions for her?

I think the attention she got from the immortal for her hard work and cleverness was really cute.