What the fk lol.
4 Inches is the absolute limit for LL(if we are talking about lengthening both segments) if you want to function somehow after it.
15k is enough but for only one segments with externals(Ilizarov and it's variations).
Where are you living if i can ask?
There are no absolute limits in LL. Especially the 4 inches you mentioned as most people can do 5 without much problems. Both segments of course.
Hopefullytaller if you push it you can maybe go to 5.6, with about 2.75 inches on femurs and 2.25 on tibias.
It maybe look weird as you are short and your legs would look huge compared to your torso but still wih clothes you probably look ok and at the height you have what matters more is the absolute height, not proportions.
So if you are lucky and have good doctors maybe 5.6 will be possible. It is still short but normallly short, a huge difference comoare your current height.