At the airport where I work, we have a good system with the training organisations. On taxi, POB is advised. 1 + 1 means 1 student, 1 instructor. POB 1 , student only. They all advise us of first or second solo circuits. When possible, I try not to give the training flight anything non-standard for the first circuit of a sortie, allows trainee to get the ducks all in a row.
We also invite them to bring their new students over for a visit. Things I like to stress is that standard phrases help, but if you cannot remember them, use plain language. If we give you an instruction that you do not understand or cannot safely comply with, talk to us. It is better to sound like a goose than have it proven.
Sending first aircraft around is not common, but sometimes with all the best will in the world to let the first on final to use the runway, it can be the best / safest option.