When to remaster video - before or after "post" ?

Newbie here and just a marketing person.

When should I remaster video?

I have a narrator who cut video against a green screen.  Should I remaster" that now, before we go into video production? There is a slight echo in her studio.

Or, should I wait until after the video visuals are added?  And then some transition sound effects.

 Thank you. - Lisa