I need a substitute for 2 T of hazelnut extract

Maybe almond extract, though I'd reduce it as it's more potent than hazelnut. Or Frangelico.

Also, if you think the recipe will take it, add a bit of peanut butter.

I think your recipe will want you to keep the nut taste rather than an addition flavor, so search out another nut extract ... walnut, pecan etc. Check out the foreign section of your food store as you might find something in the Indian or S American section. Failing that, you can consider grinding some hazelnuts into a powder and adding into the recipe.

It depends on what flavor would work in your recipe but I'd consider almond extract, strong black coffee, or a liqueur such as as a nut liqueur, Kahlua, a chocolate liqueur, etc.

Vanilla extract will be fine.