First of all, change the username, password, email, and possibly personal information. This will make it hard for the person who got their account hacked to get it back.

Secondly, you are basically free to do whatever you want with your items. You won't cause any suspicion trying to sell it, you will seem like just another gaian.
If you are into marketing, what most people do is funnel items+gold from multiple accounts into one, then sell it as a whole.