No, not exactly, although you would be understood. In conversational English, we disagree "with" something or someone. Or we have a disagreement "about" something. So, "I love my best friend, but I sometimes disagree with her about politics." Or, "Sometimes my best friend and I have a disagreement about politics."
yes, it is
The phrase "you look suspect," is grammatically correct. It contains a subject of you, the verb to look, and suspect as the direct object.
The grammatically correct phrase is "the same as hers".
Yes, as the protasis ( if-clause) of an unreal condition.
This phrase is not grammatically correct. One may say, "regardless of ... " or "whether or not ... "
Yes, 'for free', is grammatically correct.
The phrase "how don't I" is not grammatically correct. A more correct way to phrase it would be "why don't I."
Yes, the phrase "I came home at about one o'clock" is grammatically correct. It follows a subject-verb-object structure and conveys a clear message about the time of arrival.
The phrase "You are not knowing" is not grammatically correct. Instead, you can use "You do not know" or "You are not aware."
Yes
The phrase "had already left" is grammatically correct. The phrase "had already been gone" is not grammatically correct.
yes, it is
Could you please provide more context or details about what "they" are doing in order for me to determine if it is grammatically correct?
Yes. It is a noun phrase.
The correct phrase is "that was you," as the verb "was" agrees with the singular subject "you."
Yes, it is grammatically correct. "Part and parcel" is a phrase that originated as a legal term in the fifteenth century. It means an essential or integral part.
No, it's not grammatically correct. Try this: She wished she had ran instead of marrying him.