Questions about German Shephard?

Hello, I'm considering getting a German Shephard dog, and I have a few questions: 1.I have a LOT of cats. If I raise a GSP puppy with them, would cats be safe from him? 2.Are they relatively easy to be trained? Do they listen to you when you talk or do they jump and lick at you and not... show more Hello,
I'm considering getting a German Shephard dog, and I have a few questions:

1.I have a LOT of cats. If I raise a GSP puppy with them, would cats be safe from him?

2.Are they relatively easy to be trained? Do they listen to you when you talk or do they jump and lick at you and not listen?

3. We were going to put the pup in the front yard, which is about 1/4 to 1/2 of an acre, is that enough room for him or her?

4.Is ok to keep him inside the house until he is a certain age and then put him outside?

Is there anything else I should know before I consider getting one? There are a few reasons why I want a GSP, a.) I would like a guard dog, b.)I want a walking companion, c.) I don't want coyotes to come up in my yard, d.) I want a loyal companinion that will listen when I talk and not lick my hands and stuff when I pet him or her. Is the GSP a good dog for me?
Update: I wouldn't chain him or her. Half of our yard is fenced in, the other is not. We are most likely going to get one of those electric things you put in the ground around the half with no fence, reason being my cats stay in the fenced in part.
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