DiabloFans

Currently, both the keys and the demonic organ pieces (Vengeful Eye, Devil's Fang, and Writhing Spine) have higher chances to drop in higher MP levels, all the way up to 100% in MP10.

I don't want to weigh in on the current argument of whether or not drop chances should be affected by Monster Power level just yet. Obviously, we think it's a good idea and worth trying out, but if you feel differently, then I'd definitely like for you to continue discussing your thoughts on that topic. If you don't like it, tell us why. (Or, if you DO like it, be sure to weigh in too.)

I killed the act 3 keywarden on MP 10 once and the key didn't drop. (didn't have any NV stack though)
You'll need five stacks of NV in order for the keys and the demonic organ pieces to drop.

We felt this was a reasonable requirement, otherwise players could simply farm the keys in a lower MP, then set their game to MP10 and farm bosses for guaranteed drops. With the five stack, players will at least need to be able to kill monsters in that MP level in order to benefit from the increased organ drop chance.

We're reducing the reset period between character copies from 7 days to 72 hours. The change should apply retroactively, so this means that if you copied your characters over last Friday, you should be able to copy them again once the change is implemented.

So, basically (going forward), once you copy over your characters, you'll be able to copy them again 72 hours later.

Also, when the character copy becomes available, do we have to delete the current character that's on the PTR prior to copying over again, or will it just over write the current one with the one being copied from the live server?
You won't need to delete your characters. The copy system will just overwrite your current set automatically.

One more thing to keep in mind that the character copy system uses "snapshots" of your characters to copy over the data from your Diablo III account to your PTR account. At the moment, snapshots are taken once every 24 hours, so if you make some changes to your characters (i.e. buy or sell items) right before you copy them to the PTR, those changes may not get transferred over.

This is pretty standard, so if you buy a piece of gear that you really love and want to test it out on the PTR, you may want to wait a little bit before you copy your characters over.

Is the profile update a sign that the snapshot was renewed?
It's probably a good sign, but I can't give you a 100% guarantee -- not without poking around further. I can try to get that information for you, but it may take some time.

MP and Act 1
At MP1 or higher, anything that used to drop only in Act III or Act IV of Inferno can now drop in any Inferno act (so Acts I - IV). (Blue Tracker / Official Forums)

PTR Issues
We're still looking into Error 12 and Error 82, by the way. I don't have any updates to share about our progress, but we definitely know that players are still getting those errors and we're working to resolve them as quickly as possible. (Blue Tracker / Official Forums)

PTR Does Not Effect Live Servers
The Public Test Realm allows players to play, preview and test upcoming content to give feedback on new features and systems, and to find and report any bugs which may occur.

But, to coin a phrase, what happens in PTR stays in PTR. In other words, nothing that happens there will affect your live characters, their items, experience etc. It's completely separate, and when the test ends, your PTR characters are deleted. (Blue Tracker / Official Forums)