I’ve translated the wording leaked from the German site and using Google Translate this is what the list shows, note that only some are Keepers while most are considered Sentinels, so chances are these are not the full/finished status for them.
In German there is no real difference in the meanings of protector and defender, even though the German words themselfs are different. Protector translates to “Beschützer/Hüter” and defender translates to “Verteidiger”, but in the end all three words mean the same. The only real difference is when they are preferably used:
Beschützer is used in case of a more dangerous situation.
Hüter is used in rarely in general, the only case when you kind of have to use it, is when you are talking about a herd of animals.
Verteidiger is used when you are talking about a inanimate object.
It’s the same thing with almost every word which has a meaning similar to protector, defender, guardian etc. They all have a preferred translation, but can be swapped and everyone will still understand you.