Yes, 7.0.0 can be installed in Rio if you create new packages and update ie.inc.
However there are few compatibility issues. The main one is a compiler issue in Rio that prevents the packages from being built. For that you need to remove the code from two methods in iexTransitions.pas (you will see which methods when you try to compile).
Of course, this means you need to avoid use of transitions or redirect the code to a different transition.