The question is how you will handle Elesa in Black 2, I know that Joltik she has (given you're doing Challenge Mode) has an advantage against most of your team (and Sandile, assuming you caught one in Relic Castle) because if I recall, it has Energy Ball giving it Bug, Electric and Grass coverage at once so maybe Iraq or Ukraine (assuming they didn't die yet) might have to come in against it. Luxembourg might have a use given she has Limber and that says screw you to Emolga and Flaaffy's Static abilities. And if you did get that Sandile as the Relic Castle catch, I assume you plan to use that against Zebstrika.
Australia and Jamaica, being Water-types obviously have to sit out so if it comes down to those two, things will be bad. Singapore won't get any use either since all of Elesa's Pokemon have moves that counter Grass-types, except for Flaaffy.