Just wear your kilt (in the Scottish manner), and you'll be fine all night.
Can't answer your questions on which club, as these days I'm considered an old fart, and only drink in arl fella ale pubs.
Don't be totally put off by Concert square, or surrounding areas. YES. There's an extaordinary high number of pricks drink in that area, but at the same time, there's some great bars,with no problems at all, and even a little further a field ie: within about 1000-2000 yards there's some fantastic traditional pubs where there's never any problems, and people of all ages, from 18-60+
Concert square - you just have to pick the right bars..... or more aptly, don't pick the wrong ones.
Liverpool is a great party city. One of the best, and generally, if you keep yourelf to yourself you won't get any hassle.
http://www.redandwhitekop.com/forum/index.php?topic=282634.0