Replace objects with an object
I have created a circle with text in it, and grouped it all together, however I have a pattern of Circles, and only want some of the circles in the pattern to look like the one I have created and grouped, so I can click the ones I want to replace, and then with a tool, select the group I've created, and it will replace the ones I've selected. Not too sure if this feature exists, though it would be a beneficial tool to have.
The intended solution for this is to use Global Edit feature.
Copy the object you want to replace with, then select one of many copies you want to replace and use Select > Start Global Edit command.
Using Shift, unmark those copies you don’t want to affect.
Isolate the targeted copy.
Paste the copied object and position it correctly relatively the old object.
Delete the old object.
Exit the isolation and end Global Edit.
It may sound convoluted at first, but once you master the method, you’d be able to easily replace almost anything.
Global Edit has its limitations: it doesn’t work for images, text objects, clipped masks, linked objects, and third-party plugins.
Read more about it here: https://helpx.adobe.com/illustrator/using/global-edit.html
Global Edit is a way to go: https://helpx.adobe.com/illustrator/using/global-edit.html
Another solution, with a different UX approach, is to use FindReplace Art plugin by Astute Graphics.
You can do it with Copy to Objects script from here: