I'm terribly sorry to hear about the hacking and I hope this get's sorted soon. If you're in the UK, I suggest giving our Accounts Team a call on 0800 995 1079, as they may be able to assist you with your account. If you're unable to perform a Factory Reset, I suggest getting the phone flashed at one of our Support Centres. This will remove all data stored on your phone though, so I'd definitely advise backing up your phone, either online or via external storage.
It does seem as though the police know what they're doing with this, so the best we can advise is to wait for them to finish their investigation.
However, have you reached out to your email address provider to see if they're able to assist with changing your details so you can gain access?
I'm having the same problem. It's not even about security. I just want to hide apps that I don't want people to see in case somebody needs to handle my phone. Now if I hide them I can't access them either. I tried to create a secure folder but it just doubled all my apps. I don't know what happens if I sign into those and delete the originals, haven't tried that yet. I kinda understand why they made this change but the could at least be an option to show up or not on the search results. The crazy thing is that the latest searches words and the link to the app info still show up so a person can still find out whether or not you have that app installed by using the search bar.
Same thing happened to mine after the update a few weeks ago. Why did you screw with a great feature samsung???