Scheduling around prayer is straightforward if you plan for it and awkward if you do not. A two-hour appointment that spans maghrib should include a natural pause, and any decent professional in this market handles that without being told twice, but say it at booking so the timing is built in rather than improvised with colour developing on your head. During Ramadan the whole demand curve inverts: daytime slots go quiet, the hours after iftar and deep into the night become peak, and the two weeks before Eid are the busiest of the year for henna, nails and blowouts. Book Eid slots the way you would book flights, early and specifically.
Finally, think about who else is home. Nannies, drivers, visiting relatives and children all change the working environment, and a beautician needs a defined space with a door more than she needs a big one. Chemical services, colour, keratin, acrylic work, also need ventilation, so the smallest windowless room is the one place not to set up, however private it feels.