The most technically accurate translation of the second block of text would be "Usa-chan as well is capable of using phatic expressions. 'Good ni～ght!'", but I wouldn't expect a child to say something like that in English.

Sometimes making sense in English is more important than being accurate, per the TL guidelines. Could you ever imagine a child saying the alternate translation you added?

AltTranslationAccount said:

I wouldn't expect a child to say something like that in English.

dmpwn said:

Could you ever imagine a child saying the alternate translation you added?

No. No I could not. As I stated.

Regardless, your translation of that line completely changes what she's saying in a way which is clearly unacceptable. In the Japanese, she makes a statement regarding what the plushie can say, then she mimics the plushie speaking. In your current English translation, "Usa-chan can also say 'goodnight'!", she just makes the statement about what the plushie can say and then leaves it at that.

Your preferred translation of that line is debateably better than mine, but still clearly incorrect. But since this particular line seems to matter quite a bit to you, I'll let you fix it yourself.

The goal of translations on danbooru is not to be perfectly correct, but to be a good translation. If a 1:1 translation does not capture the nuance, a translation which does is preferred. See the guidelines on the translation_request wiki page.

dmpwn said:

The goal of translations on danbooru is not to be perfectly correct, but to be a good translation. If a 1:1 translation does not capture the nuance, a translation which does is preferred. See the guidelines on the translation_request wiki page.

Let me clear something up for you: your version is not a good translation. It also doesn't capture the nuance.