We've decided on a method of this that seems to be the standard way most forums approach this. This is something we're doing in several areas, since a user shouldn't go into complete shock when adjusting from one brand of software to another.
The quote button will be changed to Multi-Quote. So, you'll be able to select multiple posts to quote. When clicking reply it's going to take you to the full reply screen, adding in any quotes that you've tagged.
Quick Reply is going to be just what the name replies. It's going to reply to the first post in the topic.