Maybe just maybe you could get one on a pink or red soft jelly pellet, like those Maryuku ones, thinking it's a shrimp suspended mid water. Or get lucky when they are filtering the bottom but if they are filtering it's likely any foreign object would be ejected. Any feeding of freebies to get them going would take a long time and a lot of effort and would sure get the crabs going and still probably wouldn't work for Mullet. Mind you they do take maggot when they have seen lots near sewage outlets and weed rot. That's why I always harp on a bout feeding. Bass on the other hand will and do take anything.
I think shrimp coloured/flavoured soft jelly pellets would be worth a go on a fish packed clearwater dock for the mini species like Wrasse even if is to see how they react. On the coloured waters down Markg's way it will be quite an achievement to get mullet on anything other than the usual tried and tested methods.