Most people who come here are new to support forums and might not know everything in a mandatory list. I posted that topic as a guideline to at least provide some information.
You can probably use the Achievements plugin for this. Create three Achievements one for each type and then set them to award after X amount of activity.
The url is based on the users login and if you change it then links on the site to a user profile will break. That said, you can allow usernames to be changed. http://buddydev.com/plugins/bp-username-changer/
export db and import into mamp phpmyadmin. Then you just change the url in db. This is if you just want to test theme. If you need full plugin testing you should also download wp-content
Almost all newer Androids with os 4+ should be ok. You might as well allow the option. There are just too many Android devices to ever be 100% compatabile. If a Android device doesn’t work it is most likely a browser issue and you can suggest user to install a better browser
