Michelle A guard dog guards the house. If they see a stranger that you have not identified to them as being OK they will respond appropriately. Ellie is doing what she's genetically programmed to do. it's up to you and the other humans to show her the rules or she'll make her own.
As for playing with Dewey she's a young big dog who plays rough. She needs to socialize with other big young dogs who can take and dish out the same kind of play. You can also teach her to play respectfully with Dewey but she needs an outlet for everything else.
BTW IMO the bells on the door teach the dog to train you to respond to her. I have a client who had to take the bells down because one of the dogs was having a great time summoning her to the door for absolutely no reason except that she figured out she COULD do it. Letting dogs out routinely to eliminate is still the best way to housetrain them. Their bodies get into that routine and stay with it. Ellie should now be able to go 7 hours max without needing to pee.
Dagmar
