Learn French: Nous coordonnons le calendrier de sorte que tout le monde soit présent. - We are coordinating the schedule so that everyone is present.

Because de sorte que expresses a purpose or goal in this sentence. We are coordinating the schedule in order that everyone is present. Since their presence is the desired outcome rather than an established fact, you must use the subjunctive soit.

What would it mean if we used the indicative est instead of the subjunctive soit?

If you used the indicative, de sorte que would express a consequence or actual result rather than a purpose. It would mean that we are coordinating the schedule, with the actual result being that everyone is present. Since we are describing a goal we want to achieve rather than a current reality, we need the subjunctive.

Since tout le monde means everyone, shouldn't the verb be plural?

Even though tout le monde refers to multiple people, it is grammatically a singular entity. You must always use the third-person singular conjugation, which is why we use soit instead of the plural soient.

Could we use pour que instead of de sorte que in this sentence?

Yes, you can. Both pour que and de sorte que can mean so that and require the subjunctive when expressing purpose. Using de sorte que just adds a slight nuance, emphasizing the specific manner or way in which you are organizing the schedule.