BuddyPress.org

No. WP has one user base. You don’t need multi site to use BuddyPress

Use this link as a starting point and then read subpages. Links in sidebar

https://codex.buddypress.org/user/

It’s confusing because it has old directions that do not pertain to BP 1.7. The install process has been simplified.

http://modemlooper.me/buddypress-1-7-installation/

Try to switch theme to Twenty Twelve first. BP Columns is really outdated. Also. deactivate any other plugins especially BP plugins.

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

If I visit a reviews site, I want to read reviews so I don’t see how the conversation should be separate.
You can use group meta to store data on a group and then filter the groups listing.

You should be asking Woo Themes about compatibility.

Why posts and not just use the groups from the start?

hide with css or remove html from sidebar.php

post this on wp.org bp mobile supprt page.

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

Works with ios 6 and up and Android has some support. You need WP 3.5 and BP 1.6 +

yup, same issue

S2 members plugin might work. It can block urls unless a certain membership but it wont allow someone to buy access to a specific group.

Nothing like that exists.

I’ll fix that in next update

Anything is possible but those will require code edits.

The user account menu is in the admin bar. Looks like you have that removed.