Cal.com review
If I'm booking a camera rehearsal with two people I already know, I'll offer a couple of times in the chat. When there are six people and none of us have the same week, I'd rather give them a booking link. Cal.com lets me do that and still approve each request before it becomes a calendar event.
Give the rehearsal its own link
I'd make a separate rehearsal event and hide it from my public booking page. Then I'd send a private link to the person I expect. Cal.com lets you limit a link by the number of bookings or set a date when it stops working. Someone you send it to can still forward it, so I'd check who sent the request before I accept it.
I'd use SimpleX Chat to agree on who's joining and what we need from them. Once that's settled, Cal.com handles the open slots and keeps the scheduling out of the conversation.
Confirm who's coming
With Requires confirmation enabled for every request, a booking goes to Unconfirmed. You can accept or decline it there or from the request email. The event goes on the calendar after you accept it.
I'd pay attention to the option that holds a slot while a request is pending. That's useful if I've asked someone to pick a time and need to keep it open until I answer. Pending requests don't expire automatically, so I'd clear old ones before they eat into the week's availability.
Anabel’s take
I'd use this for a rehearsal with outside collaborators and leave the booking title plain. The two settings I'd check before sending the link are whether the event is hidden and whether every request needs my approval.