Hahaha! I have that problem with my beagle..
I know this is going to sound harsh.. but maybe seperating him from guests as i know i wouldn't like a dog chewing on my hand for attention and would not accept it from either of my 2 dogs.. The one thing to do is when he barks squirt him directly into the face with a water pistol full of cold water when he barks or howls saying the word 'quiet!' not aggressively, but firmly.. This causes shock and for some reason, helps divert their attention away.. Tell him to sit, then allow your guests to greet him, but if he gets over excited then you must seperate them again. You need to show him that sitting and being good creates fuss, howling creates a short sharp squirt of cold water that's not very nice.
As for destructive behaviour.. I can't say anything really because if i were to leave my beagle on his own free roam of the house, i'd come back to no floor etc! Just plenty of chew toys as they need their mind stimulating because they get bored easily.
You can actually buy a dog alarm in the shops or probably on ebay, it basically makes a really high pitched noise when your dog barks or howls, and apparently works!! Might be an idea into looking into buying one.
Hope that helps!! :-)