ok, so here is my general follow up to that question. What in the rules tells us that "replace" means the center of the old model and the center of the new model must be the same point?
The problem is if you are going to be getting into this game and want to play more than just super friendly games this needs to be clearer. for example Malifaux, which has TONS of wording issues in its current editon, when a situation like this occurs you place the new model base to base with the old one. if it does not fit, you do not get to put it out. that covers 99% of the situations. "replace" with no other information on what "replace" means leave way too much wiggle room. Putting a definition of what replace means will solve the majority of potential issues with it.
and yes, there are other examples of using least disturbance, but there is no evidence that i have found in the rule book that they would apply to this situation, I mean even saying something like "replace the model with the new models base within the footprint of the base of the old model. use least resistence if other models are in the way, if the model can not be placed it does not enter play" or something like that. it covers most of what will happen because even if you are center to center a small base model in melee cant be center to center with the new model. As of right now, anything related to how "replace" works is fully speculation because of the lack of a game definition of replace.
I only push on these things because I enjoy the game and want the rules clear. I am also glad facebook cleared up the crit fail in the building