My experience: 4 months to finish lengthening, was cleared to walk without crutches 2 months after that but by no means was I walking 'normally'. Probably looking at another 3 months after that before the average guy on the street wouldn't be able to tell anything was up.
I was a slow lengthener, certainly there were guys who finished up in 3 months on that part. 4 months is probably unrealistic tbh unless you're not going to lengthen much. 5 months seems doable but I strongly recommend don't go into this with fixed timescales that absolutely must be met. Recovery rates varied quite a bit when I was there, as did lengthening rates per day.