Joe - There's still time for Louisiana Waterthrush in South Florida so don't give up! Attached is a Louisiana photo to compare field marks with Northern. Note the large bill, blurry streaking, lighter brown on upperparts, bright white, flared supercilium and peach flanks. Overall it's a more robust bird than Northern but this is tough to see unless birds are side-by-side.
(Sorry for the separate post but it's impossible to add a photo to an ongoing thread.)