Peace kchughtai
You asked me a question about how did I conclude that all Rasool are Nabi, but not all Nabi are Rasool. It is fairly simple … All men are infact human, but not all humans are men. Just as men are a subset of the larger group human in the same way Rasool is a subset of the group Nabi.
A Nabi is the chosen one to mediate the matters of the ghaib from Allah to the people. A Rasool however, does this with a holy text. They both mediate matter to the ghaib from Allah to the people, but they do not both have holy texts.
To prove that all of the mursaleen had texts is to simply look at who in Islamic scriptures is called a prophet and who is called a messenger.
The rest of your post is going to take this conversation in to fallacious intellectualism … the most pragmatic way to deal with this question is to see who is called a prophet and who it called a messenger and analyse the qualities. Then you will get your answer. Let me see … I’ll get a bit of info for you now inshaAllah …