Please also address all the uses of this term in the library section.
There would be no change, although the basic source character appears in library in a few places ( it would be redefined as basic execution encoding)
The standard doesn't currently have a definition for basic execution encoding. The basic execution character set is the basic source character set plus some control codes corresponding to the standard escape sequences. The extended execution character set is that plus everything else that can be represented. The values assigned to the characters are locale-specific. There is also the wide execution character set.
Yes, the idea would be to change the definition of execution encoding such that it doesn't depends on basic source character sets - which could just mean renaming basic source character sets.
No reason to tie one with the other.
> "The values of the members of the execution character sets and the sets of additional members are locale-specific.