I'd like to see "Walk a Mile" in words incorporated more into your #2 logo. You could even keep "Third Street Clinic Healthy Living. Together." in there, but the emphasis for this project needs to be promoting the Walk a Mile campaign.
So far, I like that direction -- it conveys camaraderie and support.
#10 is growing on me. I'd like the "Healthy Living. Together." to stand out just a hare more. If you make additional versions of that logo with different colors, play with the shades of green in both the logo and text. There are some promising elements that I like in this, despite the fact they don't say "Walk a Mile."
#18 - I like the font you used, and the inclusion of both the name of the campaign and the organization. The use of the one adult holding a smaller person's hands gives the impression that the campaign is geared towards helping children or those who are vulnerable. True, the population that the public is being asked to "walk a mile" is vulnerable - but the goal is to highlight how similar we are. Could you find an image that represents a more equal relationship? Thanks (and nice work!).