All medicines you mentioned except for vetalog which is steroid, are antibiotics. I donāt know what did doctors treat in your case with them, but it is very common to develop yeast infection after antibiotics. It is because yeast and bacteria are competing for food in our bodies and on our skin ( and dogs skin, for sure). So, you kill bacteria and yeast start to flourish because of no competition. In fact, sometimes just after a course of antibiotics humans are prescribed antifungal meds.
Examples of antifungal meds you can use for dogs in tablets are itrakonazol, terbinafine, fluconazol.
I wonder if you can get them without a prescription, because they are usually prescribed, for animal and human consumption.
I think you can OTC only get Fluconazol (Diflucan). Dose for acute infection is usually 10 mg per kg, which means that in your case 60 pound dog will need 300 mg a day. You need to give it once a day for 1-3 months depending on results. After that if he feels better pulse therapy is possible - 300 mg once a week.
But would be better to discuss with some knowledgeable vet.