I'm only going to answer to the micronations question as an experimented U21 DT for various NT: It would be positive. I agree with you, there would be lots more of spanish, polish, usa players than micronations ones, but every NT have only 18 players, so it doesn't care if there's 1000 spanish players, if the micronation got 50 great players to train well. The issue nowadays it's every micronation has just a few players every season and in majority of cases, his manager don't want to train or sell him. If those players where on the transfer list, the NT manager can look for managers with intentions of training them.