When proofing active yeast, is it ok to add oil?
Generally, I've seen this done in breads where the liquids are immediately combined with the dry ingredients, sometimes the yeast will be added to the dry ingredients and then the liquids added (as for olive oil breads). But if you have to activate your yeast prior to mixing, it's generally best to allow the yeast to activate in the water for ten minutes or until frothy, and then to add other liquid ingredients and continue. 

For pizza dough, I usually skip the yeast activation (depending on the type of yeast you use, you'll have to go through a potentially different method) but active dry yeast can immediately be mixed into the dough with the water without requiring activation.