I think they are reasonable concerns especially if in areas where the client's infant child can access.

I think there is a responsibility around the specific items she's raised with you although of course there will always be something that poses a choking risk.

In terms of the food, I clean up dropped food before children leave the table. From a hygiene point of view, there's always one child who will pick up dropped food and eat it when it's fallen from the mouth of someone else. So spills are cleaned up, under table swept, surface wiped along with hands and faces before the children get down and transfer food through the house on their feet.

The crayons - Did you not have craft supplies away from regular toys?

Rocks on drive - Why would an infant be playing on the driveway even with supervision? It's a high risk location if a driver decides to use your drive to turn around and they are unlikely to spot an infant crawling around on the drive.

I do think parents should be able to expect due diligence and there's a responsibility on use to ensure our environments are suitable for all the ages of children we accept.