I can answer all of your questions with one answer. There is a time and a place for everything. Nothing you mentioned is wrong in and of itself. However, some actions may be inappropriate in certain settings. A man wouldn't wear an earring to a job interview anymore than a woman would wear a pair of jeans. Is it wrong to wear jeans? No. But an interview is not the setting for that.
Is it wrong for a Christian to have a beer? No. But maybe drinking 1 beer in front of a recovering alcoholic wouldn't be a good idea. As for whether a Christian should share the gospel of Jesus with an unbeliever over a beer, I don't see a problem. I think the message would be clouded or tainted if the Christian was throwing back the beers like it was water. However, ONE beer in a casual setting w/ a friend who is NOT a believer (and does NOT have a problem with alcohol) would not taint the message of Christ because the Biblical warning is against drunkeness, not overall drinking. I don't know a single person who thinks someone is getting DRUNK if they only have one drink. In fact, I might say it would make Christ seem more real and his human nature if a Christian shared a beer with them when talking about our Messiah. Actually, if you look at Matthew 9:10-13 Jesus teaches the Pharisees as he's eating and drinking (I'm talking about the dinner w/ Matthew, tax collectors, his disciples and sinners). Notice they don't have an issue with Jesus because he's drinking, but because he's in the company of sinful people. Jesus shared wine with Matthew (the most vile type of sinner in Israel: a tax collector), but that did not stop Matthew from receiving the gospel and following Jesus.
I'm going to put this out there. I honestly think that many of the limitations non-believers put on Christians are self-imposed by Christians themselves. What I mean is this, it's our own fault that an unbeliever may look at us negatively if we have ONE drink in their presence because some of us have been so VOCAL about alcohol being evil, in and of itself, when the Bible NEVER gives such a message. Like I said before Jesus drank wine (and yes it was alcoholic wine). Even if the water was too dirty to drink, if alcohol was forbidden he would've abstained completely and drank something else. Christians have added fence laws to God's word, and since unbelievers don't know God's word they take everything every Christian says at face value as being part of the faith whether it is or is not. I personally will NOT be bound by expectations of man when God does not have those expectations himself.
ITA! This is a good (and sensible) post.