Is it possible to change the edges for some tree level using forest package?

Question

Is it possible to change this MWE which is using forest package to produce a tree, similar to that produced by the next MWE that is not using forest? The very last level of child nodes would have to be stacked on top of each other with edge drawn from the south of the parent to the west of the child.

After reading the Forest manual, I got an impression that the key where n children=0 should be able to help, and added the line with the comment, but no matter what grow parameter I supplied, such as north/south, or 0-45-90-120 etc, the direction of growth did not change.

The solution probably lies in the pp. 10-12 of the Forest manual, but it is evading me :(

\documentclass{article}
\usepackage{forest}

\begin{document}

\begin{forest} 
for tree={
  where n children=0{draw=red,grow=120}{}, %<============
  edge path={
    \noexpand\path[\forestoption{edge}]
      (!u.parent anchor) -- +(0,-15pt) -|   
      (.child anchor)\forestoption{edge label};
  },
  l sep=10pt,
} 
[P
  [N1
    [N1C1]
    [N1C2]
  ]
  [N2
    [N2C1]
    [N2C2]
  ]
]
\end{forest}
\end{document}

Without forest (the lowest level edge is different and the nodes are stacked):

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{trees}

\begin{document}

\begin{tikzpicture}[
    children/.style={grow=down,xshift=-0.2cm,
        edge from parent path={(\tikzparentnode.201) |- (\tikzchildnode.west)}
    },
    level1/.style ={level distance=4em,anchor=west},
    level2/.style ={level distance=8em,anchor=west},
    level 1/.style={edge from parent fork down,sibling distance=5em,level distance=4em
    }
]
    \node[anchor=south](super){P}[]
    child{node {N1}
        child[children,level1] {node {N1C1}}
        child[children,level2] {node {N1C2}}
    }
    child{node {N2}
        child[children,level1] {node {N2C1}}     
        child[children,level2] {node {N2C2}}};
\end{tikzpicture}
\end{document}

Answer 1

Option where n children is the correct choice. However, setting grow changes the growth direction of child nodes, not the node itself. Thus:

where n children=0{draw=red,for parent={grow'=120}}{},

(grow' reverses the order of children.)

It goes without saying that further customisation will be needed to achieve the result shown in the non-forest example below. As it is, the child nodes of N1 and N2 are grown in the desired direction, but placed to the right of the nodes, not below them ...