No time to go through the thread so can’t say if the following had been suggested:
Some of the habits to prepare for and have some replacement “habit” - talking on the phone, getting in the car to go somewhere, after meals, during tv shows... note those moments that you mindlessly light up.
Then have something ready to replace it. One of the crazy things I thought was goofy but actually worked was taking a drag through a straw, simply taking in fresh air, but still occupied the hands. You have the idea of snacks already - sure want low-cal. Having a closed container of smoked butt swilling around in water will remind you what you’re trying to quit... And from what I’ve seen others suggest - working out, walking, running, biking, whatever you can handle and keeps you busy.
Not sure if E-cigarettes are an option but might be worth the consideration. I didn’t do any drugs or patches - went cold turkey after a serious hangover - but can understand how that may be tempting if you get really groully. After getting through the first three months, I knew I had it beat, but for quite a few years after, every three months I had to fight the urge all over again. The first 3-4 days were the worst and the first year I caught colds and flus pretty easily. But hang in there and fight this like you’ver never fought before! Wishing you the best and prayers up for your success!
That reminds me... since changing to an e-cig I've only had one cold in the past two years, no flu. Other users have similar experiences. I've read that the propylene glycol in the "e-liquid" inhibits the ability of viruses to attach to tissue; it may be true.