When using AQUAPANEL® Cement Board Rooftop on top of a metal deck, is this suitable for walking on during the rest of the roof construction?

You can, but first you have to consider the gap of the metal deck.

This depends on the gaps in the metal deck; it is suitable for walking on, as long as the gap in the metal roof is no more than 150 mm. If the gap is more than that, we do not recommend.