Questions bout some abilities

[Phelddagrif]

If i charge something with Carnifex/OOE, and it kills a model with the Battering Ram thing, and the killed model was the one that was the only one in engagement range, do I pile in and just fight, or does something else happen, like no fighting and carnifex just stays 1' away?

Another one is Dimachaeron's Leaper Killer ability, do i just move as if terrain didn't exist, or do i still have to count the vertical movement?

[niiai]

"Starting with the player whose turn is not taking place, the players
must alternate selecting an eligible unit from their army and fighting
with it (see below). An eligible unit is one that is within Engagement
Range of an enemy unit and/or made a charge move in the same
turn. If neither player has any eligible units to fight with, the Fight
phase ends."

" FIGHT
When you select a unit to fight, it first piles in, then the models
in the unit must make close combat attacks, and then the
unit consolidates.

PILE IN
When a unit piles in, you can move each model in that unit up to 3"
– this is a pile-in move. Each model in the unit must finish its pile-in
move closer to the closest enemy model. A model that is already
touching an enemy model cannot move, but still counts as having
piled in. Remember that a unit must finish any type of move in unit
coherency (pg 4)."

Usually the pile in is enough to get you in range. But on very lange bases that might not be the case. (Thunder Wolves comes to mind.)

Regarding the Dima it seems you count vertical movement if you want to finish vertically different then where you started. But why would you? Just move horisontal.

"This model has a 5+ invulnerable save. In addition, each time this model makes a Normal Move, Advances, Falls Back or it makes a charge move, until that move is finished, it can move vertically and horizontally through models and terrain features (it cannot finish a move on top of another model, or its base)."