Is there a way to mark the columns in the wall?
There are a variety of floor plan column symbols in the Column Settings, these are also controlled by MVO.
Alternatively you could apply a GO to highlight the cut fill & boundary of the column.
1, For the mvo, that's all.
2. In GOC, only Fill can be adjusted.
3. Is LINE not adjustable?
is this what you're looking for?
It also doesn't show borders
You should change the building material of the columns. Also pay attention to the building material intersection priorities.