Hey, this is Beeezie, here with your review!
A couple comments about plausibility first:
First off, I had a bit of a hard time with your portrayal of Katie as having had a crush on Fred since her second year. In my experience, most crushes people get when they're twelve or thirteen, especially on people they don't know very well, tend not to last for seven or eight years, especially when they've gone unrequited for that long. That's not to say that it never, ever happens, but it would have felt more realistic to me if she'd developed feelings a little later, or if she'd had feelings on and off for him, rather than just the strong, continuous attraction you're describing. Just my opinion, and I know that a lot of people disagree and like that sort of thing.
Similarly, the idea that Katie stared at him for five minutes seemed a little unlikely. Five minutes is a really, really long time to sit there and stare at someone, especially without them saying something about it. A minute or two would have gotten the awkward silence across without making it seem ridiculous. As a point of comparison, you did an excellent job of this when Joker returned with the letter - you let Katie's hesitance drag on just long enough that I felt myself get pulled into her feelings in that moment. I would have liked to see something similar in place of the "five minutes" thing.
Additionally, the idea that Fred and George are bad with their finances struck me as a little strange - everything we ever saw of them in the books indicated that they were very good with finances. I'm glad that you had Angelina come in, but I would have liked to see a different reason behind it.
Again, these are all pretty minor issues, but by the same token, they're not hard to change, and for me, at least, the more realistic a story is, the more I get sucked into it and want to keep on reading.
Aside from that, though, I think you did a good job!
Your characterisation of Fred was great. I felt like you took the canon Fred that we all knew and loved and put your own little spin on him to show what he might be like in this situation. Since the books were from Harry's pov, we never really saw how Fred might react to a girl asking him out, nor did we ever see what Fred might look like from the point of view of someone who has feelings for him. You were definitely covering new territory - and I absolutely, 100% believed it.
There were a lot of things that made him very believably Fred. I loved the way he jokingly bowed to her, and the fact that he took her offer in stride. That fits in so well with the bit of Fred we saw in Goblet of Fire, where he just nonchalantly asks Angelina to the Yule Ball. A lot of people would have just said, "Sorry, I have a family dinner tonight, how about tomorrow?" - but once I thought about it for a minute, I decided that you were right - Fred probably would jump to "Come over for family dinner" instead.
He was just really excellent all around.
I also really liked the fact that you've already established Angelina and George as couple-ish before Fred dies - it's obviously perfectly reasonable to not have it happen until after the war, or to have her be with Fred before he dies, but I liked this, too. I felt like it really added an extra layer to the chapter and gave both George and Angelina depth, rather than just having them there to take up space, and you used it to remind readers of the war without really dwelling on it just yet.
Which brings me to Katie.
I don't think that there's really a wrong way to characterise Katie (within reason, of course - she's not a scheming blood purist or anything), but I will say that I liked the way you did it here. As I mentioned above, I felt that you went a bit overboard at times, but on the whole, she was great. She was nervous and hesitant, but not overly so - I could definitely tell that while she was slightly uncomfortable asking him out, Fred was certainly a friend who she was generally fairly comfortable with.
What really made Katie great for me were a lot of the little touches. Toward the beginning, Katie's not sure which Weasley she's looking at, but after a moment, she realises that it's George from his smile. Given that their own mother sometimes can't tell them apart, I liked her moment of confusion and the specific trait you identified as telling her who it was.
Speaking of Mrs. Weasley, I also liked the touch of having Katie wait around for Mrs. Weasley's response and not immediately being convinced that it'll be okay for her to come. Katie never really had the opportunity to get to know Molly, so of course she wouldn't know how welcoming Molly is to most people, and it makes sense that she wouldn't just take Fred on his word.
So, yeah. Nice characterisation all around. My only issue with it was that I did feel that you could have done a little more to make Katie stand out as a character - she was well done, but she wasn't especially compelling or unique, and I didn't feel like I really got into her head as much as I would have liked. I think that part of that was that we really only saw her thoughts about and reactions to Fred - if you'd included just a few more thoughts here and there about the war, or her job, or her friends (or whatever), or a bit more of a reaction to the products in the shop, that would have worked better to me.
I also felt like you could have included a bit more detail about the shop. What does it look like? Who's in there? What products is Katie looking at? Has she used any before? I mean, you don't need to answer all or even most of those questions, I just would have liked a little more to help bring the chapter to life.
On the whole, though, nice job. :)
I've exceeded the character limit, so I'll PM you the part I cut out. I hope you find this helpful, and please feel free to rerequest! :)
Author's Response: First off let me just say WOW thats quite a review! Your advice is great and I hope to go back through the chapter and fix that and make the time frame more realistic! Honestly even though the series seems like they might be good with their finances I figured that while they had never really had money that maybe once they did they might have a tougher time keeping track of it with buying so many supplies and such. I'm so glad that you like my Katie and Fred especially since I've never tried writing Fred before! Really words can't describe how thankful I am for you to come by and leave this amazing review! but Thank You!