Edging and mulch would make those areas look better. Then add shrubs, ground cover or other plantings. You can make edging by digging a little ditch along the perimeter of the beds, or garden timbers or half buried lined up bricks. I have used the $25 rolls of 2 ft tall decorative fencing to train animals to stay out of spaces. It is easy to put up and remove. Children can also be trained. Your son should have his own special area. Make a game of placing rocks in a special bucket with a reward for a full bucket of rocks. Throwing rocks should be a no no.

That spot between the steps and the house looks like a great place to line with landscape timbers and fill with pea gravel. Add trucks, little boy, and dog; good time to be be had by all. My dear daughter loved playing in pea gravel from the time she could toddle. She's now a geologist :-)

How big is your dog? We had a flat-coat retriever who loved laying around in our liriope border. Once established, liriope is tough enough to resist digging up, and apparently soft and springy to sleep on.

Agree, you need to establish beds and then add foundation shrubs. Not sure where you live or how much these area get but I’d add a combination of evergreen and deciduous. Once you have those in you can add perennials and annuals. A few planters and a metal obelisk with vines can fill in some of the open spaces and create height.