Not quite all of them. Boris Shaposhnikov, who was a reasonably competent enough officer, did advocate for better troops and more thorough preparations during the planning phase but he was laughed out by all the other senior Soviet military leaders who thought Finland would basically undergo a instant communist revolution and collapse the moment the Red Army crossed the border.
Well, I may exaggerate a bit. But the point is that any officer going against Stalin would not have been successful in changing the overall plans, especially as - like you said - the majority opinion among the purged office corps was that Finland was a military nonentity. In fact Shaposhnikov is pretty much a case in point, as he seems to have been an officer Stalin actually respected and still could not push his views through. There
was enough information in the Red Army to know that going against the Finnish Army, especially in the dead of a very cold winter, would not be a cakewalk. There had been studies in the 20s that warned against this exact situation. The problem is getting the people deciding on the invasion to accept the challenges of the campaign and allow such preparations to be undertaken that would address these problems.