Questions about Ramayan

First question is what does Shree Ram say to Vali when he asks him why he shot him in the back and didn't fight with honour? I read Rajagopalachri's version and he skips this part by writing "and the Lord gave him an appropriate response with which Vali was satisfied" or something to this effect, this is why I hated the Rajagopalachri version. Second question what defence do people have those who believe Uttar kand isn't a later addition? Why does Shree Ram send Shri Sita away please explain the "Raj Dharm" in question that get's solved by sending her away? Also why would Luv and Kush forgive him after what happens? No matter what is told to them about Shree Ram the man questioned their mother's morality which leads her to take a vow which leads to her death. They've known only her their entire life. Rules for answers Question one is scriptural based response only no personal speculations Questions two is only for those who believe that Uttar Kand is an original part of Ramayan and not a later addition P.S. comments on the Originality of the Ramayan and other factors are please not to be discussed. It's clear I mean the Valmiki Ramayan and the one we have available today.