The Basilica de Meca is countryside Portugal, so even though there are public transports, I wouldn't recommend it. The easiest way it will be driving there, free parking available otherwise we can help out organize lifts. If your stay under a radius of 10km, a bus is being organized for picking up guests from their place to the church, from the church to the venue and from the venue back home.
Smart casual or cocktail.
We can help you organize accommodation, there are choices from Airbnb to 4 star hotels.