Can I be told when someone is late or idle for long?

Turn on the alerts you want in Settings → Alerts & emails: late start, idle too long, a long break or too much break time, too much unproductive time, overtime, a computer that stopped reporting — and, if you like, a notice when each person starts and stops work. They go by email, and to a Telegram group or Slack channel if you connect one — and you can choose, per alert, which of those it goes to (say, idle alerts only on Telegram).