The way you have structured your case across various key aspect for P2P services to thrive is note worthy. I brings out the elements which a country needs to enable not just for P2P to start and flourish but also enable its citizen to share more easily with one another. On the point of countries must have Credit Cards (CC) for P2P to be a successes cannot be a starting point, FinTech/Telco companies have wonderfully overcome this challenge by enabling mobile wallets operated by Telco companies in the emerging economies like Sub-Saharan Africa.
CC I view as a strain on a emerging economies as there is a outflow of $ in terms of fee levied by VISA/MASTERCard for their services. What the P2P platforms need to do is localise their offerings in countries where payment systems are still evolving and not see it as an hurdle. For example Real time payment systems even the most developed countries have not adopted but certain emerging economies have leapfrogged into the next era.
It must be how not existing systems adopted by developed nations solve the challenges in these countries but how technology can be made flexible, reliable and user friendly to be adopt to emerging economies. Which again have leapfrogged into the digital era.