Well. Its your prerogative. Your post. It is you who has separated the Wahi from the Messenger.
Now you have gone completely out of topic. Generally brother, when you come with a different agenda while you word the OP with another end in mind, this happens. Every time.
Anyway, there is no point respecting the OP is anymore since the creator of it himself is not. So I will of course answer your question.
1. Your gods plan question I have already answered. So please do not bring it up again, unless you don't agree and then we agree to disagree.
2. The Qur'an says to "believe in the Taurat, the Zaboor, the Gospel, Suhufi Ibrahim wamoosa, and other scripture sent to other messengers. How come you are not taking all of these scriptures and asking specifically about Torah and Gospel? Did you miss the other mentions in the Quran or did you not know about them? What are you targeting here?
3. What happened to their message? It is in every single scripture because its the same message of Monotheism. Ive already said this. But since you have an end target in your mind, you are asking it again probably expecting some answer you can hang onto and create another question with an end in mind. Go ahead. No problem. Turn this thread into whatever you have in your agenda.
Peace.
You say, the message of God is basically the same, and it came to people through different messengers. Jesus and Muhammad were 2 of them.
Let's focus on these two, as Quran gives a lot of details on Them. We cannot discuss every single prophet or messenger that had come, it will take forever.
Maybe the way you explain it makes sense to you, but it doesnt make sense to me, so, if you don't mind make the following clear:
You stated the message of Jesus was for all humanity (not just for Jews). At the same time you believe Jesus message got distorted because His Book got corrupted. So, how do you think, the message that God had intended to reach to all humanity, could reach to all people of the world correctly?
Indirectly, you are saying God failed, but explicitly you avoid to say that.
If you say, the answer is, when Jesus Book got corrupted, God sent the Quran having same message, I ask you, between revelation of Jesus and Quran, there were almost 600 years delay! Thus, with your belief All people who lived in those 600 years, were left with a corrupted message. Maybe you don't care. But what you are saying, is basically to say God failed to give His message correctly to all those people during the 600 years.