For example, among a group of monkeys were mischievous baby monkeys. In a group of monkeys, there were mischievous baby monkeys.
2. No, it would be 'explored' because it already happened recently. Anything is legal if the intention of the sentence isn't altered. But adding that/who wouldn't make sense if you added 'there' before 'were'. Or you could say "Among those scientists who were recently exploring 'terra cognita'....Stony Brook."
Student or Learner