Originally started as an experiment, while also having the influence about "the first dream visuals" :
It is just amazing how dreams begin. a bunch of objects , not having anything in common just blend in and create a unique story, before setting the final scenery for the dreamer to observe.
maybe it's supposed to create this depending on the dreamer's experience , what he saw, felt, touched, during the day. It wont make any sense at first but if you really try to decode each and every thing you see in that dream, it will just make perfect sense.
About the cross and the angel, well
I really believe they appear in the dream as a sign of Spiritual faith or awareness.
I'm not supporting christianity but these two particular symbols seem to appear and function as "Protectors" no matter what the dreamer's beliefs about religion are.
Thanks for viewing.