RE: creating a tags file for interactive search and replace regexp

[Drew Adams]

    Is there a way to do the dired-do-query-replace-regexp based on marked
    files in the standard buffer list? ... The buffer list
    will already have all the files I want and only the files I want.

Maybe I misunderstand your question, but you seem to have answered it
yourself.

`Q' (`dired-do-query-replace-regexp') in Dired does query replace on the
marked files. If you want to use it on all files displayed in Dired, then
mark all those files: `t' (`dired-do-toggle') will do that if all of the
files are unmarked to start with.

So, interactively, `t' followed by `Q' will do what I think you're asking
for.