Besides, sounds like the platter you described has just about everything you’d put in a smoked fish dip!
My logic was the opposite. Take the (your) dip items and put them on the platter as condiments. FWIW you want to lose the smoked fish while I want it front and center where I can add condiments (even modified mayonnaise) as I like and put it on some toast.
I will admit that smoked fish dips are big sellers so people must like them.