Apparently there is a non jewish woman who now will do the party planning for your simcha in Lakewood area. Go to the Gemach with you, pick up dishes, order food, set up etc.
what are the issues that have to be addressed in order for this to be a kosher event?
Table clothes from the Gemach should be washed well.
Dishes should be from a reliable Gemach.
All food should have a Hechsher that those who will be by your Simcha eat.
If there is any raw food being ordered that needs to be cooked/baked, the party planner should not be putting it on to cook/bake.
If the event is on Shabbos, make sure that you don't do Amira L'Akum. Also, make sure the place has an Eiruv (even in a hotel).
If there is wine, make sure its Mevushal.
The party planner should not be bringing her own serving utensils or knives (or they need to be Kashered first).
She may need to know about a Mechitza (if applicable) and about separation between men and women.
She may need to know about Jewish music (if applicable).
Make sure people who ask about her know that she is not Jewish so they can plan accordingly.