Four questions about ediff

[jonetsu]

Hello,

1) Deeper comparison ?

emacs ediff compare directories will list directories that are the
same.  Doing a '=h' followed by 'x' will tag and remove those
directories.  Nevertheless, going through the remaining directories
will also uncover directories that have no differences, on which '=h'
and 'x' will remove all files.  

Is there a way to actually remove all possible same directories in one
sweep without having to go through the remaining ones thinking that
they must contain something different when they are not ?  This can get
tedious over tens of directories.

For instance a main directory has 1277 files in 113 sub directories.
Amongst all that are 15 files that have differences.  Would it be
possible to get a listing of those 15 files or more likely, a listing
of only those folders in which those files were found to be different ?
And when subsequently going into one of these fodlers, to only see
what's different, without having to do '=h' and 'x' again ?

2) Use defaults for (some) prompts ?

Is it possible to handle automatically (set defaults) the following
prompts. Assuming a default of no regex for the last prompt and 'y' to
the others:

  Quit this Ediff session & show containing session group ?
  Quit this session group ?
  Compare subdirectories recursively ?
  Filter filename through regular expression ?


3) Accumulated diffed files in the buffer-selection

Is it possible to close diffed files when a session group is closed ? A
large amount of files are listed/opened after 30 minutes of using
ediff, closing them in the buffer-selection is a bit tedious.  As well
as related ediff buffers that are still lingering around after a diff
was made and closed.

4) Use a regex to focus on files to diff ?

Is it possible to to a diff of two directories with a focus based on a
text regex ?  For instance, diffing 34 sub directories but taking into
account only the files that have the string "MODS" for doing the diff ?

It would be great to be able to do those points above as it would speed
up greatly doing lengthy diffs.