Speaking where there is a lot of background noise is another. A ceremonial fire indoors can cause unique problems. Identify these conflicts as you write the ritual and seek ways to overcome them. You may need to change the ritual itself or get a PA system. For a ceremonial fire you will have to disable the fire alarm and do something about smoke.
Loss of control is another problem.
The clergy can usually handle this, but you should also pay attention to this while writing the ritual. If parts of the ritual are done in two or more different areas of control will become more difficult. Consult with the clergy people about whether they feel they can handle it or not. Splitting the participants up into groups will make it more difficult to coordinate between them. Allowing the group to break up for an Easter egg hunt is a good example.