These are the ingredients for the extracts I will use in a 5 gallon batch, should I still use the priming suger. Orange- oil of orange, alcohol, water. Watermelon-propylene glycol, alcohol, water, natural watermelon flavor
The priming sugar doesn't add any sweetness, if that's what your concern is, it just provides the sugars for the yeast to produce co2 to carbonate the beer. All of the sugar is converted.
With the extracts you are adding, you will get flat beer unless you also add priming sugar. So, yes, add priming sugar.