caller.hbs

{{es-footer}}
{{es-footer as |f|}}
  {{#f.info}}
    My custom info
  {{/f.info}}
  {{f.more}}
{{es-footer}}

footer.hbs

{{yield (hash
    info=(component 'es-footer/es-info')
    more=(component 'es-footer/es-more')
)}}
{{#unless hasBlock}}
  {{es-footer/es-info}}
  {{es-footer/es-more}}
{{/unless}}

info-main.hbs

{{this.info main=(component 'footer/info/main')}}

named-params.hbs

{{if this.info}} {{this.info}}
{{else}} {{es-footer/es-info}}
{{/if}}
{{if this.more}} {{this.more}}
{{else}} {{es-footer/es-more}}
{{/if}}
{{yield (hash
    info=(component 'es-footer/es-info')
    more=(component 'es-footer/es-more')
)}}

named_footer.hbs

<footer>
  <@info>
    My custom info
  </@info>
</footer>
<footer>
  <@more>
    Custom more info
  </@more>
</footer>