Patience, grasshopper.
Those fish will eventually outgrow a 75 I think, but if they're not too big as is it should be ok for awhile. I'd replace the picasso for the niger b/c picasso's can get rather aggressive, and the smaller tank doesn't help ease the tension. I've never had a lion but I hear they get picked on by triggers? Niger is supposedly a more mild mannered trigger, so maybe you'll be ok. The snowflake is a good addition to that tank. Hawaiian blue-spotted or valentini puffer are fun additions to a smaller aggressive.