new budgies

Hi all, im brand new here and look forward to meeting you and sharing/posting. I belong to a charity that involves walking dogs for people who cant go out. The charity also rehomes pets when the owner passes away, also fostering if the owner has to go into hospital. 0n my registration form it asked if we could foster any pets and i mentioned birds. We have a pet cockatiel. Yesterday I received a call to ask if we could home two budgies, we have had budgies before. I have a couple of questions and would value some advice. We will be getting more details later today. My first question is would it be best to keep the budgies in their cage until they have settled in before letting them out, also if we keep them in our cockatiel being inquisitive may want them to come out and play, we have some more discussing to do at home before we make a final decision but im pretty certain they will hopefully have a forever home with us. Thanks