Hi Rainy, welcome.
I think the issue with doing one leg before doing the other is that you will have a huge length discrepancy between legs for a while. Your other leg wouldn't even be able to touch the floor to be used as support. And you're just about forced to go through lengthening again to correct the difference in length even if the first round of lengthening is a disaster. I asked my surgeon about lengthening one leg at a time earlier because someone had brought it up before, and he thinks it is a bad idea. It's preferable to do femur on one leg and tibia on another leg at the same time if you want to do both tibias and femurs at once.
I think the most that will happen with convential CLL methods down the line is that an internal device will be developed that is even more reliable in working/not malfunctioning. The principles of Ilizarov are going to be the same no matter what is used to lengthen, so I think there will always be pain and struggle in this process. As far as non-CLL methods to get taller after adulthood, perhaps there will be a way to open up the growth plates to allow growth once more. Probably will take a lot longer than 5 years time though. I don't see anything happening within that short a time period.