"Well, then, why this hound should be loose to-night. I suppose that it does not always run loose upon the moor. Stapleton would not let it go unless he had reason to think that Sir Henry would be there."

1）why this hound should be loose to-night. 这句中的should是表示“居然，竟然” ，说话者表示惊讶等意思吗？

2）Stapleton would not let it go...中的would是表示预测（=过去将来时）吗？