Please read carefully to avoid ambiguity in the use of Google terminology.
I linked my Google Play Games Game to my Google Play Game, and then I had to remove this link in the Google Developer Console. I recreated the link and my SHA1 code became available again. Now I received a message that my previous project will be completely removed from Google Developer Console. Will it also be removed from Google Play?
AFAIK both serves different purposes, google play is used for launching apps, where as developer console is for using various API's provided by the google.
So Once you delete your project from developer console it will be gone from google developer console not google play console. and but you can restore it until 7 days of deletion.
Google play console is used for publishing, updating or deleting your Android Apk from Google PlayStore.