Mirdiff is a no no..
Its a residential area that is far from all the tourist activity, it is however right next to a huge mall city center.
There are no bars within a 20 km radius of mirdiff.
now for the 5%
as i said i am out of touch but you could check out
http://www.timeoutdubai.com/nightlife
as for dive bars? there are hundreds they range from hip trendy ones with house music blaring from them, to live rock bands to quite ones
it depends on your type of scene.
now ibis and novotel are good choices they are both owned by the same company , i would recommend the shiekh zayed road location.
nobody cares what you buy from Duty free , the customs wont even bat an eyelid.
about the frames.. they call this place dobuy for a reason.
its all people do, shop..
remember you can bargain in most places..