Sorry, I seem to have missed your second post.
Basically I think you got them right. Your translation is really good.
I'm just adding some comments or minor corrections.
「ねえ。プレゼント、
何がいい？」また、由香里ちゃんが聞いた。
"Well, what would be a good present?" Yukari-chan asked me again.
what would you like for a present?
「うーん。何でもいいよ」 私も、また、
すぐにそう答えた。
"Hmm. Anything would be good" I also answered again
right away.
つぎの日曜日は、私の誕生日だ。
Next Sunday is my birthday
「
まいちゃんたら。何でもいいって言うのが、一番 困 るのよ」
(I really don't know what this sentence means. Specifically, what does "まいちゃんたら" mean? Does the "たら" mean "if"?)
Oh, Mai-chan! "Anything will do" is the most difficult.
たら is to emphasise one's feeling. Surprise, exasperation, disgust, annoyance, embarrassment, etc.
「
だって、ほんとに何でもいいもん」 私は、おなじ答えを繰り返した。
"Even so, really, anything would be good" I repeated the same answer.
Because really anything is OK for me.
朝礼の時間。放送大の所で、先生がいった。
It is time for the assembly. In the auditorium, the teacher/principal? said
At the morning assembly.
Could 放送大 be 放送台? Actually I've never heard of 放送台, but considering the situation (at the assembly), it could mean the platform with a microphone with a stand. There can be some exception, but generally school assembly is done in the school yard/field (outside) in front of the school building at Japanese schools.
「今日は、子供のえコンクールに、入選した人の表彰式をします。二年生の古谷由香 里さんが、金賞に選ばれました。古谷由香里さん、前へ 」
"Today, for the children's drawing competition, we will do the commendation ceremony for the person who was selected. 2nd grade Kotoni Yuraki-san wins the gold prize. Kotoni-san, (come up) to the front."
古谷 is either Kotani or Furutani.
子供のえコンクール must be either 「子供の絵コンクール」 (title of the competition) or 子供の絵のコンクール (which sounds more natural, as a generic words.)
由香里ちゃんが、高校先生から、表彰状を うけとって いる。
Yukari-chan has received a citation? from a highschool teacher.
Yukari-chan was receiving a commendation certificate.
This expression (as if the event is on-going right now) is sometimes employed to show the scene lively. (like a live-broadcasting.)
高校先生 sounds very strange for me. Definitely 高校 should not be highschool, but just a proper noun (could be different kanji??)
私は、拍手をしながら、自分の事のように嬉しかった。
While clapping, it was has delightful as though it was my own. (She was as happy for Yukari-chan as though she herself had won).
Your interpretation in the brackets is closer to the original sentence.
教室に戻ると、だれかが言った。「古谷さんて、え 上 手なんだ」When we returned to class, someone said "Yukari-chan sure is good at drawing?" (This is just my guess, but I really don't know)
Back in the classroom, someone said "Furutani san, you are good at the drawing." (As if the person did not know the fact until now.)
え should be written in kanji, 絵.
由香里ちゃんは、えへっと笑っただけだった。
Yukari-chan, just laughed at the picture.
Yukari can just gave a short laugh. I found it difficult to translate this particular way of laughing えへ.
She did not laugh at the picture, she showed a kind of smile with her mouth a little bit open to her classmate who complimented on her drawing skill.
When complimented, many Japanese feels a bit shy, so it is a mixture of pleasure and shyness at being complimented.
