Participants List

Part 1, sometimes when using the "Meet Now" option to set up a meeting, the Participants list is populated with people in my Team/Organization, but often it is not. How do I set it always to show everyone on the team?

Part 2, I often meet regularly with people from outside my organization. Currently, I have to find and then copy/paste their email address into Teams to request that they join the meeting. Is there a way to integrate Outlook contacts into Teams so that I can search by name when adding people to the impromptu meeting?