Sorry I think these questions were covered in your previous post about this. Didn't the "how-to video" cover this?

Whether they require cold stratification on not depends on the variety and you don't know the variety. If northern grown then yes the odds are they need it. If southern grown, probably not. Your choice. All you can do is try it both ways and see what happens.

How successful? Unknown since it is not the normal way to grow blueberries so it is seldom done...

It takes several weeks to germinate if they do and then several years before they produce fruit if they survive.

Dave