"My beautiful cousins" is indeed a perfectly grammatical phrase. It is, of course, not a complete sentence.
No, the correct grammar is "Are these my beautiful cousins?"
No, the correct grammar should be: "I am pleased to catch a glimpse of your beautiful face."
No, "will be had" is not a correct grammar. The correct grammar would be "will have."
The correct grammar is: "Are those correct?"
No, the correct grammar would be "I hate you the way you hate me."
"July has just been started" is not correct grammar, instead the correct grammar is "July has just started."
No, the correct grammar should be: "I am pleased to catch a glimpse of your beautiful face."
I surprisingly received these beautiful flowers on my birthday.
No this is incorrect grammar. To make the sentence grammatically correct you should say: One of my cousins came yesterday.
No, "will be had" is not a correct grammar. The correct grammar would be "will have."
No, it is correct grammar, not a correct grammar.
"On a train" is correct grammar.
no_____If the sentence is You do do that (meaning You are in the habit of doing that) the grammar is perfectly correct and the sentence 'does have correct grammar'.
"July has just been started" is not correct grammar, instead the correct grammar is "July has just started."
Grammar.
This will be an exciting month is correct grammar.
The grammar is correct as it is.
No. The correct grammar is "would give"