Comment / Reply system

We're a non-profit looking for a chat comment & reply system for our community to talk with each others. We currently use HumHub for our chat section, but we're looking to expand into our own system to integrate it with our new site that we're making. On our new site, we're using a program called PHPRunner to develop what we need, so it must integrate into PHPRunner as well. Simply put, we're looking for a wall type post script made up with the following specifications: • User can post onto a wall and have it load without reloading page with AJAX • All users that are marked as active in the database are e-mailed about the new post • Users can click a link to view the post • Users can reply to post without having to reload page using AJAX • When a user replies to a post, the original poster, and anyone else that has replied gets an e-mail of the reply. • Only 1 level of nested replies to the original post. • Users and commenters can post images that’s a thumbnail, clickable to view in a lightbox/gallery view if there are multiple images uploaded. • Users can like the original post or individual comments. • The wall shall have an infinite scroll. Comments will be limited to showing the 5 latest, with a link to AJAX load up previous comments, 10 at a time. • Posts and comments will show that they were posted ‘x’ minutes ago up until 1 hour, then ‘x’ hours ago until 12 hours after, then the post date and time after that. • Users can have the ability to turn off e-mail notifications from individual posts, or the entire wall altogether. • When a user clicks a link to view an individual post from an e-mail, it will only show that one and not the entire wall. • Admin/Board members can delete and edit all posts. Users can only edit their own posts, but cannot delete them. • All links will transform into a hyperlink, and videos or other media will automatically OEmbed • Admin & Board member groups can pin a message to the top for everyone to see. • User posts/comments will show their name and profile picture, if uploaded. • Users can turn on email notifications for individual posts if they want to follow, but don’t want to reply. • Design MUST be responsive for mobile. Prefer to have a bootstrap style design that changes could be easily adaptable. • PHP 7.3 and MySQL 5.6 is what’s being used. DB is InnoDB • Must be able to be deployed on multiple sites with ease. Alternative is to modify humhub to work with our software. • E-Mails have to use PHPMailer, but also have the option to use SMTP in the future. Budget it not very high due to us being a non-profit, but looking for quotes to have this done. I've included a screen shot of how it would look as an example from HumHub. Thanks