Thank you for your answers everyone.
So, per your comments, I can continue with my EASA licenses and ratings with an ICAO PPL, but since the cheapest way to do the whole ATPL curriculum is by completing my IR while hour building, i.e. before my CPL, and because IR requires me to be an EASA PPL holder, it's best to hold an EASA PPL. Am I correct?
Now assuming that I understood you right, since the conversion from an ICAO PPL to an EASA PPL requires me to have at least 100 total flight hours and with me already having about 50 flight hours after my ICAO PPL training in Tunisia, can I do my hour building in Europe and as soon as I get to 100 total flight hours pass my EASA PPL exams (Air Law, Human Factors) and skill tests which will then allow me to do my IR?
I know I'm overcomplicating things here, but haven't we all done it in search of the best and cheapest flight training formulas? Thank you for your patience anyway!