What would be the best way to call the field selection values from the parent entity's field that is located on the same page. This would allow for conditional fields based on fields in the parent node.

There is a big disconnect here with Field collections and extremely large entities that are consistently changing, growing, or shrinking. In those cases it is easier to add field collections to the parent entity and modify or delete those field entities as you go. The catch is as stated above. There really needs to be an easy way to still pass the information in the parent to the child field collection for these complex and large entity set-ups to work.