This is the original crew (Venkman, Spengler, Zeddemore, and Stantz).
This scenario takes place near the end of the events of Breath of the Wild; they have been accidentally summoned to assist the heroes in defeating and sealing Calamity Ganon.
If they need help, they can summon the Extreme Ghostbusters, the 2016 crew, and their IDW counterparts.
*The trailer for Breath of the Wild II suggests that Calamity Ganon was just another Phantom, since its... original source... is still around.
Which is why, for the purposes of this thread, Calamity Ganon will be considered a ghost/phantom/spirit.