The Mingle Forum plugin has been removed from www.ads-software.com for download, but the plugin support forum is still available. The link I posted above goes to another link that states that this plugin has had a known security vulnerability since April 2013. I really don’t know anything else, but I assume that WordPress has removed the plugin because it has a known security vulnerability that has not been fixed yet.
If you remove the Mingle Forum plugin and install BuddyPress then you would use BPS just like you would normally without doing anything else. If you are asking about how to customize your additional .htaccess file then you would follow the example code I posted above…
But here is what I think really needs to happen. Read this WordPress Codex link about what to do if your site is already hacked.
https://codex.www.ads-software.com/FAQ_My_site_was_hacked