Jeanne saute dehorsen bondit.

Would seem somewhat more natural, even if "bondir" just like "jump" in English, would naturally give the sentence some kind of stylistic effect

À l'intérieur, dansà un cours de karaté.

Des enfants en uniforme de karatéegi coupent du bois.

We never say "uniforme de karaté" (in France at least), but always "kimono"... which is incorrect because it actually refers to the traditional dress-like Japanese garment with long sleeves and a large belt
These years, the correct term "karategi" has grown more and more popular

Une fille adorable âgée de sept ans, les cheveux blonds courts bien tirés en arrière, l'uniformeun karategi trop large pour elle.

Elle est l'une des deux filles dans leu cours.

Better with a complement introduced by "de"

Un vrai garçon manqué/une vraie garçonne.

Both are synonyms but with different connotations. "garçon" definitely has a social/cultural connotation, with the early XIXth century (feminist) women wearing short hair etc. "garçon manqué" is more common, but might also be derogative in some contexts (which isn't the case here)

Dans l'autre main de Dolly, un sabre- laser.

Dolly : C'estY aura Dylan, Jack, et Holden.

If she's talking about who will attend her next party, this would definitely be the way to phrase it so any reader can immediately understand what she's talking about

Dolly : Elle veut pas faire due camping.

Absolute negation = pas de, plus de

Jeanne : Je sais pas si je veux que tu traînes qu'avec des/les garçons, chérie.

"LES garçons" in this context could refer specifically to Dylan, Jack and Holden (the already mentioned/definite boys in this context). "Des" would disambiguate

Alternatives to "honey", for a kid => ma puce, mon lapin, mon trésor, mon chaton...

Ils sont plus marrants/amusants.

"marrant" if you want the colloquial "funny"

Jeanne : Je vais en parler à/avec la mère de Dylan.

This one would be better since the focus here is talking about a particular subject, not just talking in itself)

Peut-être tu peuxque tu pourras faire du camping, mais pas dormir sur place.

"peut-être" starting a clause => peut-être QUE

Dolly lui lâche de la main.

lâcher la main à quelqu'un

Jeanne : PCommence pas de(à bouderie), Dol. !

There would be tons of ways to phrase this naturally. When a child starts sulking, acting out, a very natural thing to say is "commence pas !". You can say "commence pas à bouder" here, since you repeat it with "ça" afterwards
but "to sulk" is "bouder" or even (in an ironic, joking way) "faire du boudin"^^

Elle souffle fortement, en fait des tonnesfait son cinéma/fait des manières/fait un caprice.

"to huff" can also be "maugréer" in this context, but this sounds quite formal
"en faire des tonnes" would perhaps be too soft in this context. All these options at the end would be good translations of "being/playing the drama queen". For someone throwing a real tantrum, you can go until "piquer une crise"