I was considering going freelance myself and these are questions I also considered. I hope someone with experience replies and we can turn this into a very useful post.
Yes. When the user opens the app I will get their current location and add it to a column in the database 'currentLocation' Then I will query the database like so: select * from users where userOnlineStatus = 'online' and currentLocation = ""; <- That is what I would want to do. Its just calculating the distance so that not all random users are showing up.
I'm not too sure but flappy bird the game only got successful overnight because someone hated how crap it was and posted it onto Buzzfeed. Then it went viral.
I'm not certain but I think its because HN wishes to promote positive up voting not down vote trolling like reddit etc... If its good It will get up voted, if not then just don't upvote it.
Yeah the pro performs very well for me. If you are wanting to get into Swift there are some awesome beginner tutorials here: http://ios-blog.co.uk/swift-tutorials/
Pro has more power. The big projects will need it. I chose a pro when I was doing my iOS stuff as my mate has an air and Xcode just killed his resources when running the app simulator.
I also heard this before I went to see the doctor, I just said that it was affecting my day to day activities and that some days I struggles to force myself out of the house. I said My friends and family are also noticing and then the doctors seemed to listen and referred me. The list was about 5 months before I got seen and I heard that this was quick.