I'd say Havok will be the first Hellion and Emma will be leading them. That seems fairly predictable to me. The conflict in UU will not be between the New Mutants except MAYBE Emma-Charles, Emma-Dazzler (just a little but probably not) and Scott-Alex. Depending, of course, on how the plot unfolds, the Hellions can either be friend or foe. I cannot however see them having any ties to the Brotherhood, not if Emma Frost continues to be involved. Her philosophy of non-violence woud prevent it but there is nothing to rule out a leadership struggle. The Hellions were younger mutants in 616 and they were an independent bunch.