The problem with using .html() and .fadeIn() together is that .html() triggers a hide/show event which doesn't allow for animations to continue. Try the code below and see if it works

Code JavaScript:
$("#projectnav").html(ajax_load).load(getURL(this), function(response){
    $(this).hide().fadeIn(1000, function(){
        $(this).text(response);
    });
});

As for not been able to add multiple instances of code into the document ready method i have no clue about that one as it should work find unless theres errors in your script.