Ok first off there is not a air rifle that I know of that could take down a coyote or even a fox. The biggest I think you could get to would be a coon. Second are you looking for a .177 or .22caliber air gun because the options you listed have both. Gamo makes a air shotgun/ air rifle combo that would do for birds, squirrels, etc etc. Kinda pricey tho. Check out the video: http://www.gamousa.com/Catalog.aspx?Product=71
Good Luck.