have sth to be done 和have sth done 的主要区别是不是在于，一个是将来要去做，一个已经做过了？

have sth done 仅仅强调某事被做，并非已经做过
例如：I'm going to have my hair cut.我将要去理发。能理解为头发已经理完了吗？ 显然不可以。
也许没有have sth to be done 的用法
表达将来要去做—— will / would have sth done
表达已经做过了—— have / had had sth done

是的。理解完全正确！

不是，举个例子：
I will go to shanghai, do you have anything to be taken?所以前者的意思是做定语的感觉，to be taken修饰anything
I will have the agreement typed,所以后者的意思就只是让某人做