In those sentences, the pronoun "quanto" has esclamative meaning, not interrogative; so the sentences may be translated to «We had so much fun!» and «We laughed so much!» (this in order to express the same meaning; however I know there's a literal use of English which includes "How much fun we had!» and «How much we laughed!» as esclamatives). "Alzare il gomito" is completely the same as "bere troppo" (alcholics), however it's a little more friendly but not less formal (they're both informal): the difference between these expressions is the first is less direct, as if you wished not to mention the action of getting drunk (because you're talking politely and don't want to mention unelegant actions directly, or because you just want to imply the meaning and let your listener understand). Generally speaking, "bere troppo" is so direct that it might sound rude, so I'd use it to stress the fact I think someone does wrong drinking too much, or in a very familiar situation. "Alzare il gomito" is clear all around Italy... but you got it right supposing in daily life nobody cares. The choice is up to you then! :) Thank you very much from me and – I'm sure of this – all the other answering Italians. We're always pleased to help you and answer to your interesting questions. Buona giornata anche a te!