Yes, of course it's a good idea. The key is getting the word out that you are having it. Advertising is one way, but it's expensive. Another good way is to post flyers (legally of course) at various apartment complexes in your area. Apartment complexes are where many future first time homebuyers live, so that's a good place to generate leads.(Secret: The Laundry Room is a great place to hang fliers if management will let you. People sit and dream a lot in laundry rooms, they are also captive and bored) Obviously also post a sign outside the office.
As to your other questions: Keep it short and sweet. Concentrate on answering their questions. Make sure you ask if they have questions frequently (interaction will generate loyalty, lectures will not). No lenders, no pressure. I wouldn't give out prizes, which could be misconstrued as inducements, but I would supply coffee, tea, and donuts. Keep it light, optimistic, and fun.
If it gets you nothing else, it builds confidence and poise which will help you in listing presentations.