Hiya, sounds like you've identified & have all the risk under control
To open it up a little - re-evaluate or reflect, is it possible to have a staff member deployed to stay within/around the home corner? Scissors are such a huge part of hairdressing it seems a shame to omit them due to what might happen. Maybe organise the environment a little to include the scissors in role play rather than at the drawing table?
Move the focus of using scissors to cut real hair to cutting dough and wool hair. Build pictures for a stylists gallery -
face outline?
To help you feel more reassured you could also send out a note to parents letting them know what you've planned or will/have been doing with a hairdresser theme, explain that whilst you've focussed on cutting things other than real hair the children may have a heightened awareness of scissors, hair and the effect of cutting.
Invite feedback so that everyone's happy with what's provided - if you know head lice are present in the setting, cradle cap, alopecia or a skin condition/infection you could perhaps use dolls & soft toys for brushing/combing/accessory dressing
If you do find attempts are made at cutting real hair staff can intervene gently by explaining that people train for a very long time to cut hair neatly. If the children say they do cut neatly, agree & ask if they want to be a hairdresser later, explain how it's not always a good idea to cut own or other's hair because if they accidently cut it wonky or not how someone else wants it, hair takes a long time to grow back.
A great theme for exploring people who help us - hair professionals, bug busting and basic care routines/all about me - wash, dry, brush.
Hope you have fun xx