The equivalent request to "Please sit" is "Have a seat." (uses the noun form)
No. He sat by the window is correct. He sits by the window is the correct use of sit.
The correct is *me neither* .
The correct spelling for the expression is "ouija."
The correct expression is Repent of.
Did he ask her is the correct expression.
That is correct.
It's a correct English phrase or expression.
"Discuss about" is incorrect. "Discuss" is correct.
Yes, it makes more since than my father and I. Either one is correct it depends on the situation. Your father and you can sit in the front seat. My father and I will sit in the back.
"For some reason" is correct. Some, in this instance, implies "one or another" instead of multiple, so "reason" would be singular.
No, Belying her utter terror, Natalie maintained a calm expression is correct.
"God help you" is the correct phrase, as it is a traditional expression of sympathy or encouragement. It is not a grammatically correct sentence, but rather an idiomatic expression.