Q: multiple ownership of devices

Hello DRD01, 

Thanks for using Apple Support Communities. 

Based on your post, I see that you and your wife have separate Apple IDs, but ownership of your devices isn't always correct. You would like to know if this will cause any problems. I completely understand. It's nice to have your devices associated with the correct Apple ID. I can assist you with this. 

First, use Check your Apple ID device list to see where you‘re signed in and learn which devices appear in your Apple ID device list, how to see your device's details, and how to remove a device, if necessary. You only want to be signed into your device, with the Apple ID you are using. 

Then, I would advise both of you to log into the following site with your Apple ID, and then associate your devices with each Apple ID:

My Support Profile

You also mentioned using the 'Find my' feature on your Mac. I would like to share a couple of articles that will help you with this:

OS X El Capitan: Use Find My Mac

OS X El Capitan: Use the Find My Friends widget​

Best Regards.