Bulmers and Magners are the same thing, bottled under different names. I have seen bottles of Magners in Ireland. I am not aware of more than one flavor (super yummy). Cider has about the same alcohol content as beer. I've been told that bottled is better than draft because it's fizzier. If you like bourbon, try some Irish whiskey. Jameson & ginger is a common drink (Jameson whiskey, ginger ale, and lemon wedge). I don't remember being in a pub that didn't have a full array of spirits and liqueurs.
Also, pubs have very good food. For a tasty, filling and cheap lunch, order the soup of the day; it's vegetarian and thick and comes with fresh baked black soda bread and butter, all for €5.
Having seen what goes on in pubs in Ireland (especially hen and stag parties), unless you are stark naked, I don't think you will stand out, no matter what you do. You can also stand for a few minutes and/or wander through the pub listening to the music - if you like the music and the ambiance, get a drink and stay. If you don't, go on to the next one. If you want to smoke, you can take your drink outside with you.
Explore the pubs. They are often a warren of different rooms (and more bars) and very interesting. Talk to the other patrons. Everybody in pubs is talkative. Actually everybody in Ireland is talkative. I guess it's the Blarney Stone.
One of my tour guides was an Israeli woman who did her master's thesis on the Irish pub. She lived for weeks at a time in Clifden (a town of about 2000 in Galway) and spent hours every day in one of the pubs , never drank a drop of alcohol and became good friends with half the town.