Hey there,
You can download the attached
creation_date.js,
publish_date.js,
creation_date.php and
publish_date.php file into template override location which are
JoomlaFolder/templates/yourCurrentTemplate/html/com_easyblog/composer/panels/post/general/creation_date.js,
JoomlaFolder/templates/yourCurrentTemplate/html/com_easyblog/composer/panels/post/general//publish_date.js,
JoomlaFolder/templates/yourCurrentTemplate/html/com_easyblog/composer/panels/post/general/creation_date.php and
JoomlaFolder/templates/yourCurrentTemplate/html/com_easyblog/composer/panels/post/general//publish_date.php.
Can you have a try and see how it goes?
Can you improve that? Can you at least allow dates since 1872 (the first book published by the author/philosopher I'm studying)?
From what we see so far, you are the only person who want to set below the 1900 year, perhaps you can submit your feature request regarding 'request for change this minimum year requirement' simply by creating a new ticket on the forums, and set it to "Feature Request".
If more people request this as well, we will consider it.