1#. Go to community, click on messages under the drop down arrow, scroll down to the name you chatted with. If you see it, click on the name,now to your right hoover over that persons name and it will show your there new name.
2#. You can also try to run a CID number of the one your looking for . CID number will never change from the account it was created from no matter how many times a name change is made. So if you get the CID number and google the persons name it will alway bring up other names that might be that person as well or even there 2nd hidder account. If its there account your looking for just run the names that google gives you and see if the CID number matches,
3#. And one last trick is if they ever gave an review in shop with there old name google will show what they posted and what they said and all you have to do is go look at the creators shop and look at all the reviews and find the one that matches the one she/he posted and it will show the new avi name of that person.