For someone your size you should be doing rolling 48-72s. You should have a few hours between fasts where you are refeeding. Some people take vitamins, some dont. You could take them with your refeeds if you wanted to. You CAN drink non calorie drinks during your fast, but Cole doesnt recommend it. Tracking calories on refeeds wouldnt hurt so you dont binge and consume 3 days worth of calories which is surprisingly easy.
Start with 16s and work up to 24s, (you can just eat like 500 calories, have avocado toast or something) don’t try to do 48s right now, the toxins you’re going to release will make you feel pretty crummy. I also highly recommend supplementing high quality minerals and nutrients, your body is severely deficient right now, and it will really help you shed the weight.