I saw in this post (str_replace_all problem) that it appears that I am missing a 'replacement value' but I thought the " " in the stringr::str_replace_all("\\.", " ") was the replacement value (i.e. white space)?
You pass iris as the first argument of rename_with. The second argument has to be a function. I put a ~ in front of your series of stringr functions to make it act like an anonymous function. I could then refer to the column being acted on as .x and used that as the first argument of str_replace_all. The arguments of str_replace_all are str_replace(string, pattern, replacement) and your were missing string.