1) While i'll be in my initial training stage in the first year (PPL+CPL+IR) will i be able to work part time (20 Hrs/week) to cover up my living expenses ?
You cannot work in the US to support yourself whilst training.
Do not consider coming to the US if you know that you need to earn money in order to support yourself. You won't earn any where near enough.
Remember you have to pay your own medical insurance etc and that alone can be costly.