Miles

Our first meeting with miles, is slightly different real note we hear of him is regarding his dismissal from the school:

"They absolutely decline."
"They go into no particulars. They simply express their regret that it should be impossible to keep him. That can have only one meaning." Mrs. Grose listened with dumb emotion; she forbore to ask me what this meaning might be; so that, presently, to put the thing with some coherence and with the mere aid of her presence to my own mind, I went on: "That he's an injury to the others."
At this, with one of the quick turns of simple folk, she suddenly flamed up. "Master Miles! HIM an injury?"
" Why, he's scarce ten years old."

With this conversation between Mrs. Grose and the governess, the reader gets two opposing sides of Miles.
The first is that he is a rather nasty child. They dismissed him, as in expelled. However, the gentlemen at the school went into no detail. So for what reasons he could be getting dismissed for that is still a mystery. However, the governess buts it as, "that he's an injury to the others." Though i dont know exactly what that might mean, it seems probable that it results from the idea of the student in class that is always a distraction. Especially in a school that is private, and for the upper class, any student that may pose as a "bad example" will probably not be tolerated for very long. So just based off this the reader's impression of Miles is not good, rather it seems that he is spoiled and obnoxious the opposite of what his sister is. It would seem like he has no manners and is being sent home because he can not behave himself.
The other view is that of Mrs. Grose's- first she is all disbelief. Its as if this could simply not be true because it is contradictory to his character. Then she invokes the idea of how young he is, to show that whatever the problem is its probably not his fault. She quickly displaces the blame from him onto the headmasters at the school. She later on invokes his appearance, demanding that the governess see him first and then judge him. But even if his appearance is angelic that shouldn't dictate what his actions maybe. With looking at Miles through Mrs. Grose's view, readers would get a very different sense one that is more consistent of a grandmother. That Miles is naturally sweet and just generally misunderstood. Like with Flora readers are too masked and uncertain at this point to be able to make any real assumptions about her.

Flora

here's the first description of the little girl, Flora.

The little girl who accompanied Mrs. Grose appeared to me on the spot a creature so charming as to make it a great fortune to have to do with her. She was the most beautiful child I had ever seen, and I afterward wondered that my employer had not told me more of her. I slept little that night

This particular description followed just after the description of the house being so beautiful. It definitely seems as if the governess is simply being blown away by all that she has seen. With the little girl's description/appearance, she adds on to the feeling that all this is otherworldly, almost too good to be true. She is the little doll she is holding in her hand.
She is first described as a "creature" as if her beauty goes so far beyond normality that she can not even begin to be compared to other humans. She also comments on her surprise that her employer has not talked more frequently, or rather, bragged more frequently about the girl. It's as if for the governess this girl is such a gift that the whole world should know of her perfections.
This also goes along with what we've learned of the governess so far. Again she says it was "on the spot" as if she is so caught up with what's going on she doesn't stop to wonder about it all. The perfect horror hero would have already been suspicious, but this governess is not, rather she is the classic naive female who never suspects deception until it occurs.
With this opener passage of the girl, depending if as a reader, one is generally hero/naive. Anyway if the later, like the governess, you will be very caught up in the description of the girl and house, and will not be able to wait and see what the rest of the story leads to.
If the former, then you will automatically know that you should be watching the little girl for anything suspicious. Like the old saying goes if it sounds too good to be true it probably is.

I remember as a most pleasant impression the broad, clear front, its open windows and fresh curtains and the pair of maids looking out; I remember the lawn and the bright flowers and the crunch of my wheels on the gravel and the clustered treetops over which the rooks circled and cawed in the golden sky. The scene had a greatness that made it a different affair from my own scant home, and there immediately appeared at the door, with a little girl in her hand, a civil person who dropped me as decent a curtsy as if I had been the mistress or a distinguished visitor



So that's from the text, and it's the narrator's first view of the manor house where she will be living for the next few months/years, however long. Like Jane Eyre, the governess (for she never has a name) is actually treating the experience of the new job as in its a new type of liberty and that she is truly privileged for being there. Everything she sees there is exciting and fantastic to her.

Especially with this scene when the governess first comes up to the house she is astounded by what shes found. the image presented here is idyllic, a little doll house. The immediate reason she likes it so much is because of the difference between it and her own "scant home" the people are "civil" and "distinguished" and she feels important there as if she is some "visitor" or "mistress" who deserves the utmost respect. At this point in the story line of her adventure, even though the readers know its supposed to be a scary book they are almost as taken away as the scene as the governess is because they weren't expecting something so nice. She even describes the curtains and the air in the most splendid way. They re not just trees but rather "clusters of trees" they are not just curtains but "fresh" ones. As if everything in the house is untouched just as it should be. The windows are open, showing that the weather outside is also pleasing.

The readers also get a good look at how the voice of the narrator/speaker might go. he seems sweet and non judgemental, but most importantly she also seems to be naive. She becomes that classic horror story character. going into a place you think is going to be just ideal but in the end you pay for your inability to expect a surprise or something suspicious