Well, this was strange. It's not really a shipping fic, and very weird for a crossover. All it really is is humanified Pokemon and Sonic characters randomly interacting by one telling the other to mow a lawn. The appeal of crossovers is seeing characters who come from very different worlds leading very different lives interacting and surprising one another. In the end, you could have replaced Latios with any random boy and Amy with any little girl who needs a stronger person to do a favour and help her find her friends.
Anyhow, this story was cute, and parts of it were written nicely. The way Latios and Amy interact is amusing, although she seems more mean than usual. I also liked the way you describe Latios working and Amy criticizing him, but Latios puts up with it for his little sister. I liked the way you did those parts, although the actual part with Latios working is really short compared to the rest of it. But hey, it still works well, and it would have been boring if you had made it too long, so I think you did a good job there.
There are a few small problems with this. For instance:
1) Latias is silent, doesn't move, and is apparently on Latios's back the whole time! I know she's asleep, but even sleeping people move around or yawn or maybe even sleep-talk a little. The problem is that because she is silent for the entire story, you could take her out completely and the story wouldn't even change. When a story is the same with or without a character, you have a problem - Latias isn't a ghost, right? Also, you never say that Latios put her down while her works, so it sounds like Latias is still on his back the entire time. You should definitely mention that he puts her down at some point, and maybe she yawns and rubs her eyes and asks Latios why they're not going home before she falls back asleep.
2) Why does Amy have to vandalize a field that belongs to somebody? Why couldn't she just find a clearing outside the village? She could have "borrowed" the farm owner's tool without telling him, which would still make Latios annoyed. But Latios seems like a very conscientious, moral person, so it's hard to imagine him agreeing to doing this.
3) If Amy has been here for three days, what on earth has she been doing for so long? Isn't she afraid, or hasn't she found food and shelter? This would be an interesting part of your crossover, exploring how a character would be lost and confused in a new world. It's kind of boring when you don't talk about it.
4) Amy is from a different world. In her world, usually rings are the type of money, and in Pokemon, their money is some kind of Yen or Pokedollar. Since they use different money, she can't really bribe him with money, because her money comes from another world so he won't be able to use it in the Pokemon world, or even know what it is.
5) Amy makes Latios make long, perfectly even lines in the sand. This doesn't really make sense, because all fields are made up of perfectly even lines. Sonic would never realize this is a sign from Amy because to him, it would just look like any ordinary field. Writing "SOS" might help more.
6) I really, really have trouble seeing Amy and Latios as a couple. For one, Amy always has and always will love only Sonic, so why would that change all of a sudden? For another, Amy was totally rude and mean to Latios, so why would he like someone who was rude and mean to him the whole time? The way they start acting at the end seems totally random, and doesn't really make sense the way it happens. If Amy is lonely and she sees Latios as being kind and helping her when nobody else will, that would help. As for a reason Latios might like Amy...I really can't give any ideas, because I'm clueless. Like I said, she's totally mean to him, so I don't see how he could like her.
And there were just a few small grammar problems, very few.
This is just a small problem of bad editing, which you probably could have fixed by rereading it a few times before posting. The problem is that he has dark blue...what? You forgot the word "hair" here.
He stood about six foot seven; had short dark blue with two small parts of it spiked upward on both sides on his head.
This is a recurring problem in this story. The first sentence here is past tense because of "said," but the second sentence is present tense because of "seems" instead of "seemed." You keep switching tenses in this story, going from past tense to present tense randomly. Again, the more you proofread your story, the more you will catch these mistakes and edit them before your readers do.
“Sonic?!” a voice said from in front of him. The voice is what seems to be a girl’s voice.
Another case of a missing word. I think you meant "What are you looking at anyway?" This really shows how important it is to proofread before posting.
“What are you looking anyway? What do you want? Kidnapper. Stalker. Sexual Harasser,” the girl asked coldly.
This isn't a mistake with your writing - in fact, these are perfectly good reasons, and it makes sense! Especially the point about his little sister. Unfortunately, we once again have a little problem of Latios being a little sexist.
“First of all, I don’t like to take orders from random people. Unless you have an important role, I defiantly don’t take orders from females; especially one that appears to be ten years old and thinks she’s ‘all that’. Second of all, you can commit the crime yourself. I’m not about to go to jail, seeming that I am parenting my little sister here. So no thanks,” he said.
As I said, most of his reasons make sense. Not taking orders from strangers is a good reason! However, the way he says he doesn't take orders from females sounds a little bit rude. The problem is this: it makes sense to not take orders from random people, especially people who aren't important or who are little kids. This makes sense. But the way he says he doesn't listen to females sounds wrong and mean. This is because it implies that Latios will happily take orders from just about any male, just because they're male. But the second they're female, it's like Latios won't respect them. That's the problem - it sounds like Latios just doesn't like females and doesn't want to respect them, and that makes him a little bit sexist.
The way to fix this problem is this: instead of saying
"Unless you have an important role, I defiantly don’t take orders from females"
You can say
"Unless you have an important role, I defiantly don’t take orders from anyone"
By saying "anyone," Latios will sound smart and reasonable, instead of sounding like he only listens to men but dislikes and doesn't respect women. I know it's not what you meant, but that's what it sounded like, so you should definitely fix it asap. Please let me know if this makes sense.
Anyhow, to answer your VM, this doesn't really need to go in Shipping, and this is the correct place for a crossover since it involves Pokemon. This is a cute story, but it has some problems. Most of them, like Latias being quiet as a mouse or switching tense, you can change easily by rereading it and making small changes. For the most part, you still did a nice job, and the way Amy and Latios interact is definitely neat, and you wrote it nicely.
Please think about what I said. I hope it helped. Good luck!