Comments can currently only be used with nodes, and they really should be able to be added to any entity type.
It seems like this could be done by making comments a field that is added to an entity or just providing an admin interface where you select which entities that comments should be able to be attached to. The latter might be easier to implement with the current architecture, and from a data perspective we'd just need to add an entity_type field to the comment table (and rename nid to entity_id).
Recent comments
With JQuery, simple and fast. Or put all possible links in one menu, and hide unnecessary with CSS mediaquery.
Different primary menus depending on the viewport size?
I wonder if what is happening here is the default database settings are for utf8mb4 if the database server supports it. In settings.php or settings.local.php if that's where you put your...
Problem with utf8mb4 Format when importing database
I've not done this with a menu before but something similar with different Views presentation blocks for different resolutions (i.e. not just responsive but a different presentation method...
Different primary menus depending on the viewport size?