URL selection function that is designed to randomly assign users to different surveys until full
You seem to have a fair bit of hard-coding there. I would suggest instead something like:

PATH_MAX = 10
WIZARD_COUNTER = {'/surveyone/': 0,
                  '/surveytwo/': 0,
                  '/surveythree/': 0,
                  ...}

def start(request):  
    if WIZARD_COUNTER:
        survey_url = random.choice(WIZARD_COUNTER)
        WIZARD_COUNTER[survey_url] += 1
        if WIZARD_COUNTER[survey_url] == PATH_MAX:
            del WIZARD_COUNTER[survey_url]
        return render(request, 'start.html', {'survey_url': survey_url})   
    else:
        return render(request, 'surveyfull.html')


This makes it much easier to alter the number of surveys in the future, you just need a dictionary mapping {url: count}. If you want to have different counts, the simplest way is to set the PATH_MAX to whichever you want the most of, then preset individual counts to PATH_MAX - count_for_that_survey.