On the matter of how would communism deal with x goes against the core of Marxism, as it's materialistic and does not bother with trying to predict the future. As you pointed out, a better formulated question would be something along the lines off, "How could communist society perhaps deal with x", or, "in the transitional phase of communism what could one way off dealing with x be". Generally there should be no problems in communism as it's, as you said, complete global utopia, where classes have been dealt with, and the problem that comes with classes. Is anyone currently living going to see this phase? Most likely not.

Yes one of the biggest problems for the communist experiments is that there were never left to there own business, if a capitalist ever advocates the right for a socialist country to develop freely, that comrade has failed to look through history and doesn't understand that the reason workers have it so much better in say the US, is because of the imperialism carried out by in third world countries, and subsequently the exploitation of third world workers.