Your original question title “watchlist column” was to vague and did not describe your request for other viewers. I have updated the title to better reflect the context of your request.
Here is the code for the VWAP column.
def data = reference VWAP().VWAP;
AssignBackgroundColor(if close > data then Color.GREEN else Color.RED);
Here is the code for the ema cross. (this has already been asked and posted elsewhere in the forum)
input lengthOne = 8;
input lengthTwo = 20;
input maTypeOne = AverageType.EXPONENTIAL;
input maTypeTwo = AverageType.EXPONENTIAL;
input priceOne = close;
input priceTwo = close;
def maOne = MovingAverage(maTypeOne, priceOne, lengthOne);
def maTwo = MovingAverage(maTypeTwo, priceTwo, lengthTwo);
AssignBackgroundColor(if maOne > maTwo then Color.GREEN else Color.RED);