The main risk from household sewage is microbial pathogens. These tend to survive best in the gut and not well in aerobic conditions outside the body, such as a compost pile. I would have no problem at all putting those grass clippings into the compost.
I would have used firstimegardener's strawberry plants, since 1) toxins in soil are not necessarily taken up by plants, 2) it is unlikely a tiny strawberry plant could carry enough 'load' of toxins to make later fruits risky, and 3) in fact the composition of *fruit* is going to be primarily based on what the plants are growing in when they fruit, and since they would be transplanted to my garden and growing in good clean soil, the fruit should be fine. JMHO, YMMV.
A gardener once posted on a composting forum that he had used Milorganite (compost from Milwaukee's sewage plants) on all their flower beds and had tomatoes sprouting all over. His wife didn't get it till he explained that the seeds can survive not only the human digestive system but the sewage plant. She would not touch the tomatoes! It's all semantics I think, it's not like that tiny seed, having been through 3 decomposition steps, is going to contribute more than a gnat fart to the tomatoes.
BTW, much of the produce sold in the US comes from places where they *do* use sewage sludge. Given the choice between storebought and home grown from a plant started in sludge compost, I'd take the home grown!