What you can do is hide that menu option option from non-logged in users. To do this, you need to install the WPFront User Role Editor plugin and it gives the the ability to choose who can see each menu option. It’s quick and dirty but also easy. Obviously is any not logged in user knows the address of the activity page they can still see it, but you could also set that page to private.
There’s no easy way to do this I’m afraid, in this case I would unload all plugins except BP then load invite anyone and then each of your chosen plugins one by one until the site fails again, then you know which one is to blame.
That’s strange, I use invite anyone on a number of sites so I can confirm it works.
Have you tried deactivating all plugins except Buddypress and Invite Anyone to see if that works?
If it does, it’s a case of activating the other plugins one by one until you discover which one is causing the conflict.
IF you are getting the 500 error you may not be able to get to the Dashboard to deactivate plugins, that being the case you should FTP to the wp-content/plugins directory and you can delete the other plugins from there in order to get your site back.
I’m not an expert but I think that would involve doing a template overload of the user profile php files and editing the files in the members/single section.
Other than writing your own code I think that’s the only option, you could ask @henrywright the plugin creator to add it as a feature but I’m not sure he’s in favour of it.
This seems to be more of a bbPress issue, since it is to do with the ordering of the forum. I would unload all other plugins and see if the problem persists, also switch to the 2016 Theme.
I think you need to provide more information about this error, Buddypress does not normally work with posts so I would like to know why you think this is BP? If you unload all other plugins does the issue still appear?
The user should get an email with and activation link
By the way, this activation email sometimes ends up in the Spam bin on the users email, one fix to this is to set the outgoing email address used for this email using a plugin such as https://wordpress.org/plugins/cb-change-mail-sender/
#1. You create a blank register page and then you go into the BP page settings and select that page to be used as the registration page, you also need to set wordpress settings to allow user registrations in settings>>General
