Expansion card questions: When i use Summoning Spell to get Black Panther in to play, can i get Summoning Spell back?

Yes. Black Panther (ally)’s ability specifies “After” he is put into play, you then attach a Leadership card to him. Once Summoning Spell puts Black Panther (ally) into play, it would have finished resolving, and Black Panther’s ability would then trigger.