#1:
Code:
ChatFrame1:SetMaxResize(UIParent:GetWidth(), UIParent:GetHeight()
ChatFrame1:SetMinResize(100, 10) -- this and the previous line might not actually be needed
ChatFrame1:SetWidth(400)
ChatFrame1:SetHeight(200)
#2:
Code:
ChatFrame1:SetClampRectInsets(0, 0, 0, 0) -- needed so the game doesn't push it away from the edges
ChatFrame1:ClearAllPoints()
ChatFrame1:SetPoint("BOTTOMLEFT", UIParent, "BOTTOMLEFT", 7, 7)
#3:
I'm not sure what you mean, as the chat edit box is below the chat frame and matches the width of the chat frame by default. If you're seeing something else, it means you have an addon moving and resizing the edit box.