Are these sentences correct?

Dimanche la semaine dernière, j'ai vu ma cousine.

Dimanche 16, j'ai joué aux cartes.

5 answers

I'll send this to our French expert, SraJMcGin.
Dimanche, le 16, ......

I'd also use a comma in the first sentence = Dimanche, la semaine dernière, ...

Otherwise, it looks fine.

I'll flag this in case you have additional questions.

Sra (aka Mme)
Are they also pronounced the same way?
Also, is it okay to omit the day of the week and say just "le 16"?
I don't understand your question about the pronunciation. It is the typical French pronunciation.

Yes, it's OK to just say "le 16."

Sra (aka Mme)