I'm going to slightly disagree with jbc and say that some doctors will not recommend this surgery simply based on morals or the fact that they are also, in a way, biased. While we focus more on benefits and less on risks, they focus on risks and less on benefits. I've met an endocrinologist- a well reputed doctor that thought a 5'2 male getting this was completely unnecessary. Their opinions
can be outdated and like he said, ultimately it has to be
you who takes every input- forums, doctors, etc. and makes the decision of whether it's worth it.
To answer your questions:
1. Is 7.5cm's achievable for my height?
Yes, but with internal femurs only, and they're very expensive. 7.5cms for your height is actually going to be easier since your bones and muscles are already bigger, than say someone 5'4 that's lengthening 7.5cms. Something like Precice 2, even in India or Africa(counting travel & stay) will be $50K or more, and with Paley it'd go in the 100s.
2. If yes, will I be able to do everything athletic-wise that I can do right now?
With a good recovery, you can return to casual sports.
3. How do people save up the money to do Leg Lengthening?
Jobs. Parents. If they want to save, they do externals in India or China, but externals won't give you 7.5cms.
4. How safe exactly is it to go to places such as India for Leg Lengthening?
Safe if you go to a good doctor. There are many bad doctors in India. If you mean the country itself- going to India where you'll stay in a big city and only move between the hospital, the airport and the hotel, you'll be safe.