Does the average Order 66 survivor know that Palpatine is a Sith Lord?
Been some time since I've seen Rebels, so it's possible this is contradicted there and I've forgotten. That said, this is what I understand the average Order 66 survivor would know.
Things you know:
One decade before the Clone Wars, the Sith were officially confirmed to be back.
The Clone Wars, while mostly a political conflict, was tied up in some kind of Sith plot; you know this because Dooku was a Sith.
You know there is political tension between the Jedi Order and the Supreme Chancellor's office. You're probably aware of him centralizing power. Your Master or your best friend in the order has probably griped about it.
Suddenly, your clones turned on you and you barely managed to escape. You can't figure out why this happened.
After a beacon initially calls you home, it suddenly starts blaring a message to stay away, no matter what. At about the same time, Palpatine, who you've likely had negative opinions of, if only from a political perspective, has declared himself Emperor. You are now a fugitive.
A few months or years into being on the run, you encounter another Force user for the first time since the clones turned on you, except this one is working with the Empire and has the trademark evil red blade.
Things you don't know:
You probably didn't know the extent of the Jedi Council's investigation into Darth Sidious. You might not even know he exists; I'm unsure of whether or not this was made public within the Order.
You don't know Palpatine is Sidious. You very well might not know he's a Sith Lord, just that he's seized power. This was kept from the public, unless you were a high-ranking member who knew about the investigation or were present in the hangar when Anakin Skywalker rushed to tell Mace Windu something, you don't know shit.
If you're lucky, when you encounter that other Force user for the first time, you live long enough to learn they're an Inquisitor. But you've never heard of an Inquisitor before. You have no idea where this person came from, all you know is that they're trying to kill you on behalf of this new world order.
You definitely don't know who Darth Vader is.
With all of this in mind, being on the run as a Jedi during this time period has to be really, really confusing and terrifying.