It’s amazing how few zooty options are available to do birthdays in SharePoint without workflow, custom development or 3rd party tools.  The modern site pages were not an option because the navigation all gets messed up, and the pages can be emailed to the whole company by anyone.  This was not an option for the team. Plus they are rank amateur beginners who need to take the platform over, so it had to be kept simple.  We used everything out of box in classic SharePoint and did the following :

We have the birthdays in a standard Custom List with the telephone list, (it’s a medium sized business, so this is easy to maintain).  We created a calendar view for birthdays.

We created a standard Picture Library with a view to display today’s birthdays and views for each month.

We added the default Newsfeed web part for people to add wishes.  We added a one-liner copy/paste script popped into the Script Editor Web Part to hide the word “Newsfeed” so we could add our own wording.  That script is :

<style>.ms-microfeed-siteFeedTitleArea{display:none;} </style>

We made a banner and dropped the lot onto a site page.  And that was that.  All they have to do is upload the photos into the Picture Library, and change the web part views on the first of each month for the ‘all month birthdays’ list.  Then they send the link out via the internal communications system with a message.

We also added a “no birthdays today” pic for the in between days and just did a filter to include that picture.