Is there a way to make someone invisible/make an item make someone invisible?

yeah but you can add them in after sometime with another team switcher maybe using player ids

That is not possibel, invisabits are not a thing yet, and there is no other way to make a player invisable.

Even if you were to do this, it would not allow for them to move because they have to follow a player.

true. I didnt think of that