In case you missed it during the lead up to the Seasonal Days break, Google "graduated" three Labs for Google Mail early in December. Graduating Labs means that functionality previously labelled as experimental is now part of the base software, usually as a setting on your M+Google Mail account. These new settings might already be enabled on your account; if not, check your Mail settings to enable them.
You can enable Send & Archive and Default Reply All from the General tab in your Mail Settings (located under the gear icon in the upper right of your Mail window). Quote Selected Text is done by selecting the specific block of text in the message you're replying to, and then hitting reply. Only the block of text you selected is quoted in the reply email -- there's nothing to enable for this functionality.