How bad is this French note I jacked up from Le Robert?

Factual Questions
1

Remember, only an asshole uses slang from a language he’s iffy with, and an even bigger one uses it writing in a language where the elementary grammar is something of a mystery…
Pierre,
Merde alors! Mais bon sang qu’est-ce qui se passe?

Qu’y a-t-il au menu? Eh bien, quand je suis rentré à la maison je découvris un mets nouveau (bonheur, étoile, etc):

[INDENT]Cahier de Exercices Orthographique et Chiffres de La Langue des Signes Américaine marinée au Sauternes saupoudré de flocons de tabac et poussières en cartable

Qui a oublié le bouchon?
Votre pote,

Leo, et Buddy le Superchien[/INDENT]

2

What I had in mind, goofing around purposely, is:

Pierre,

Shit! What the hell happened? When I got home I discovered a new recipe (happiness, star, etc.):

Exercise book for fingerspelling and numbering in American Sign Language marinated in Sauternes, powdered with flecks of tobacco and random dust en cartable.

Who forgot the cork?
Your Pal, [if archaic, it’s ok.]

Leo, and Buddy the Wonder Dog [that’s his full name, but I switched it to Superdog thinking that Superman is understood as a loan word.]
The last part of the recette should stay in French, as in en croustade (in a crust), but here it was in my messenger bag/book bag/satchel.

If there’s a word for “random crud/lint you find at the bottom of a briefcase/pocket/whatever,” which won’t mess up the punch line of en cartable, it would be all the better. I think.

3

Pretty good. My suggestions (underlined):

(…)

Qu’y a-t-il au menu? Eh bien, quand je suis rentré à la maison, j’ai découvert un mets nouveau (bonheur, étoile, etc):

Cahier d'exercices orthographiques et numériques en Langue des signes américaine, mariné au Sauternes, saupoudré de flocons de tabac et résidus divers, en cartable

(…)

Votre pote, <== This is singular (only one pal) and presents an odd mix of formal and casual. “Vos potes” is plural, “Tes potes” is plural and familiar.

Leo, et Buddy le Superchien