Is it possible to keep the photos on the iPhone and iCloud in-sync? So if I delete a photo on the iPhone, I want it to be deleted on iCloud and vice versa.
Is it possible to configure the phone/cloud to do this?
Yes, if you enable iCloud Photos on the iPhone, your iCloud photo library and the iPhone's photo library will automatically be synchronized. Then if you delete a photo on the iPhone, the same photo in the iCloud library will automatically be deleted.
You'll find the guide for turning on iCloud Photos here: