一、这是A及B各人的房子。
This is A's and B's house.
Ans：这是个别所有格，所以应该为复数故应为 These are A's and B's houses.

二、他有四头狗；一头是黑色的，剩下其他的皆是白色的。（指其他三头）
He has four dogs; one is black and the others is white.
Ans：the others 应为复数，所以应为 He has four dogs; one is black and the others are white.

三、他有十头狗；一头是黑色的，别的狗是白色的。（指其他部分的狗）
He has ten dogs; one is black and others is white.
Ans：同二，He has ten dogs; one is black and the others are white.

非常感谢您解答我的疑惑，真谢谢您！