Hi! I will be soon a owner of a little CZW (Spettro is coming home in six weeks, he's two weeks old now
). I do not know about the second and third question but...
1,8 metres can be enough if it's a quiet type. But as you do not have the certainty... raise it to 2 metres at least and with a upper part bent on the inside of the garden. It makes your garden looking like fort knox? Yes, but it's safer.
Make sure the fence is stud and strong and that it is not possible to dig under it... they do it too!
Good luck to you too!!