(1) 掠夺 and 劫掠 are almost the same, and I think can be interchangeable.They both mean to rob.
掠夺 could mean to literally rob people of their assets.
It can also refer to abstract actions. For example, if warlords exploit the wealth of a region by suppressing the people and monopolising oild supply illegally, they are 掠夺ing these people. They are taking away money/natural resources from these people with force.
劫持 normally means to abduct/kidnap a person or a group of people as hostage, orto hijack cars, air planes, and other such vehicles, usually not for the money these people have with them but asking for ransom.
劫道 specifically means to block a road in order to rob the people or vehicles. 道 here means 道路 (road).
2. 夺取 means to take over something, such as to seize/occupy a city during war(夺取某个城市的控制权, 攻占某个城市), to take control of a country(夺取政权) .
抢夺 is basically the same. There can be a subtle difference. 抢夺 could imply to take control of something very quickly.
In Chinese Criminal Law, the difference between the crime of 抢劫 , 抢夺 and 盗窃 is this:
------抢劫 is to forcibly ask people to give out their money. This involves violence and injury towards the victim. For example, if someple stopped you and forced you to give money to them, they are 抢劫ing you.
------抢夺 is to publicly grab people's properties very quickly. The difference from 抢劫 is 抢夺 does not involve personal injury to the victims. If someone suddently grab your mobile phone and run away, he/she is 抢夺ing your phone.
------盗窃 is to steal. It doesn't involve violence towards the victim and is not done publicly. The victims don't see their action and are not supposed to know that.
----- The difference between 盗窃 and 抢夺 is 盗窃 is done without letting the victim know. 抢夺 is they know the victims will see their action. They do it in front of the victims very quickly and run away fast.