No vaping and smoking before and during LL is a no brainer and everyone who does so needs to stay away from surgery until they stop.
I used high shoes and insoles a lot, almost never walked around barefoot, and I must say my calves did indeed feel shortened. Initially I had some struggles with some exercises and needed to do calf stretching even though I am femur LL. However, after a few weeks now my calves are good to go I don‘t need to stretch them anymore. So yea I think for tibia LL maybe you should stop a few months beforehand but I agree with Paley’s sentiment that the stretching is 99% during lengthening and not before. Rn I would say if I stretched before it would have maybe spared me a few sessions of calf stretching if anything (but not wearing high shoes would have done it better - however was impossible with my mental health)