complete paths after non-space

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I'm migrating to zsh and find it differs subtly from bash.  Three
immediate look-'n-feel diffs I'd really need to reset to
bash-compatible behavior...

1.  completing path names with leading non-space

I often want to complete filenames in options where you have things
like --file=/wrong/path/name, whereby you go back and fix it, or enter
new things after the non-space-starting pathname sequence

Bash happily completed it while in my current zsh setup I have to
insert/delete a space prior to the pathname.  An easy way to make it
the same?

2.  in-place ^r search

-- zsh offers an underline, and I don't want it

3.  completion offers must go away faster

-- zsh lists them in the underline(s) and they seem to linger there
longer than in bash, can I banish them faster?

Cheers,
Alexy