the famous movie star got in the car quickly with him follow

第一问.这里是一个由介词with引导的一个伴随状语的介宾短语,是状语当然不能和主句并列在一起了.当然如过改成这样就可以了the famous movie star got in the car quickly and he was followed by a group of fans.这样的用法是为了避免结构上的重复,和简单
第二问,你的疑问是对的.是非谓语动词做了后置定语,而且V-ed 的形式表了被动
再问： 是状语当然不能和主句并列在一起了 那个是状语？ 主句是哪个？
再答： the famous movie star got in the car quickly 主句 with him followed by a group of fans伴随状语从句