I remember that scene. When I first watched the movie, that is one of the scenes I gave up trying to understand manually (by listening over and over to each line).
Listening to the first line a few times again (at the beginning of the film), I think it may be possible he is simply saying "au revoir". The first part "au" is missing, but it appears his mouth is moving and the mic didn't pick part of it it (or it was accidentally edited out), and of course the rest is muffled.
For the line later on, "le chat pas à l'école", it also seems it is a shortened, colloquial manner of speaking. "The cat's not allowed at school." Or, "No cats at school."
Your work on the dialogue between the girls in the schoolyard is excellent!

You wrote that you had to do it several times. Do you mean several whisper passthroughs, or listening by ear?
Some things I noticed, some of which I assume you've already noticed, but I'll mention them anyways:
80
00:15:47,440 --> 00:15:48,496
and I was riding it.
---> it might sound better to say "I used to ride it."
The French
imparfait tense still confounds English speakers who are trying to learn French! It likely still confuses AI. Similar in German Präteritum, perhaps?
85
00:16:15,190 --> 00:16:16,984
Are you Israeli?
---> Interesting to note, it certainly sounds like she is whispering "Israeli", but the Bulgarian subtitles ask, "Are you Jewish?" My speculation shows my own large cultural gap, but I assume she already knows the other girl is not Israeli, but I am sure Bulgarian has a proper word for Jewish. We might consider which is better for the localization of this line.
83
00:16:02,620 --> 00:16:05,820
I was also born in Vienna
and I want to go to Paris.
---> It sounds like she says she wants to go to Paris ("et je veux que Paris" my best guess, it is missing an essential verb), but the subtitles say "I have lived in Paris." I would vote in this case to leave it as "I want to go to Paris" as I don't recall if the movie ever hints at her previously living in Paris.
There is the possibility of "
Je suis née à Vienne et je ne veux qu'à Paris," which could mean, "I was born in Paris, but want only to live in Paris." Chatgpt suggested "I was born in Vienna, but I want nothing but Paris."
89
00:16:31,340 --> 00:16:34,680
If they had not been saved,
they would have been killed.
---> She certainly says something like "S'ils n'étaient [été?] pas sauvés," which is indeed "If they had not been saved," or "If they weren't saved," but subtitles also suggest, "If they had not run away." I get the impression the French dialogue was an afterthought. It feels more intuitive to keep the subtitles as a translation of what is spoken, but the Bulgarian subs offer up just how they were "saved." Really, this is just more ideas to consider, rather than a correction of your subs.
91
00:16:38,880 --> 00:16:40,580
I have returned.
---> "Moi, je suis revenue." Might make more sense to say, "Me, I came back," or, "Me, I went back."
Continuing your subs.
16:43
À cause des Allemands?
Oui, Yanni m'a amené. C'est un Grec. [could be "Yannis m'a emmené"]
Was it because of the Germans?
Yes. Yanis brought me. He's a Greek.
Tout avait comme nous [or, Tout à fait comme nous.??]
Nous sommes allés de Vienne [deviennent??!!], à Prague,
de Prague à Paris, à Belgrade. Au present nous sommes
à Sofia. Ici, il n'y a pas de Fritzes.
Et maman dit que nous partirons bientot pour l'egypt.
Comment t'appelles-tu?
Greta.
And mine's Elitza.
It was the same for us. [The same that we went through.]
We went from Vienna to Prague, from Prague to Paris, and then to Belgrade.
For now, we are in Sofia.
There are no Fritzes here.
And mom says we'll leave for Egypt soon.
What's your name?
Greta.
Et moi, Elitza.
Sofia is the capital of Bulgaria
"There are no Fritzes here." The Fritz, slang term for German soldier.