Do not knead the dough at any stage. When you knead, it develops gluten and can make your maamoul hard.
You can use other fillings than dates, you can fill with crushed pistachios or walnuts as well.
You can use a cup of only olive oil, ghee or butter rather than a mixture, however, Sawsan mentions that the use of all three gives a better texture and flavor and I have to agree to it.
The amount of sugar mentioned is almost to nil. Increase the sugar in the dough or alternatively serve the cookies sprinkled with icing sugar.