The correct answers are: The caterers are to arrive at exactly 4:00 PM at the side entrance. The bride's father is bound to cry during the toast, so I should prepare tissues. The band is due to start playing their first set at 8:00 PM.

"Are to arrive" is used for formal arrangements and instructions.

"Is bound to" acts as a semi-modal expressing a strong future certainty or prediction.

"Is due to" is the correct structure for scheduled events.

"On the verge to collapse" is incorrect; the correct idiom is on the verge of collapsing.

"Will have be arriving" mixes up future perfect and future continuous; it should be will be arriving or will have arrived.