OP, with all due respect, you're probably better off sticking to one of your posts here and asking questions there instead of creating multiple new topics.
Most of your questions can be answered in various threads on this forum anyway. Not trying to be rude at all, don't misunderstand.
My understanding of arm lengthening is that the nerves in the arm are more susceptible to damage then those in the legs. Speaking from experience from an arm injury I had in my teens, I believe that to be true. I had a compound fracture in my right arm that required a sort of plating to resolve, and my ulnar nerve has never, and will never be the same.
An example would be hitting my "funny bone" on that arm is painful enough for me to lose consciousness.
I've never seen an LL'er that had obviously short arms, neither in pics on this or the old forum, or in the 12 cosmetic patients I have spoken too in real life or over skype.
I do not think arm lengthening is necessary or worth the risks.