No, he's asking if he needs to run a full spike thru the whole thing and if he can attach each cake to the styro lifts using some royal icing............
So, no, you don't need to run a full length dowel thru it. These types of cakes are best stacked on site. I wouldn't transport it already assembled and I wouldn't allow a client to transport it/stack it, either.
Dowel each tier, as usual, to accommodate the styro lift and cake above it. Sit the lift on top of those dowels and then the cake onto the lift.
Yes, some royal on top of the lift will adhere the tier [on its own board] very nicely. Sticky fondant [just some rolled fondant mixed with water] is my go-to if I don't have any royal on hand.