Joao brothers aka Felix and Cancelo looks really different when they were playing in their old teams and when they play for Barcelona, I expect Barcelona will sign both of them permanently. Barcelona need to prepare at least 200 Million Euros because Atletico Madrid tend to ask ridiculous amount.
Barcelona will definitely want to keep the both of them, but i don't think they can because of their current financial situation, Manchester City and Athletico Madrid will ask for quite a lot of money for a permanent transfer for each of the players, coupled with their salary/wages. I expect both Joao Cancelo and Joao Felix to return to their respective clubs after their loan spell is over, and from there they'll prolly be sold to another club that has the money to buy them.