Brazilians do use more than just isso, although the frequency of use of this and other terms might differ from European Portuguese 
Yes, Eu vou para casa is the appropriate phrasing when you don’t plan to leave again. As you’ve noted, a and para often imply different durations of movement, as discussed in detail in this other topic: "A" or "para" with verbs of motion?
Esta prenda é para vocês is perfectly correct too. Para is the only acceptable preposition in this sentence.