I'm beauty, not hair, so can only speak from my own experience.
Excel at it. Excel at cutting or colour (more money). Colour corrections, condition of hair and care. In my local town, there are about five hairdressers on the high street. I chose the one I go to because it looked quite funky(!). It's run by two guys. I like them, but if something opened near I would move. They don't take cards and the toilet is minging. The salon has a great vibe but I don't really want to listen to loud funky music for two hours.
My cut is pretty good - not amazing, and my colour is okay. In all my years I've had one hairdresser do good colour, but she had all her family in and out all day and on the phone. It felt like the bloody Waltons.
My point being this. Don't dilute your skills with different. Make your different your excellence. I hanker for a hair experience like the beauty experience we offer. Calm tranquility in the mad oasis of life. Gentle music, wifi, good coffee and a clean toilet. If you can cut hair as well, result!!!
I have grown my business beyond recognition by concentrating on skin. I do all the other treatments, but skin is my speciality. I have hiked the prices of my facials right up and our turnover has soared. I'm looking at more staff to carry out the brows, nails and waxing.
By all means do the mini treatments, but I would look at these as maybe Thursday, Friday and Saturday packages. Night out, brows, hair, make up etc, but your money is in high end cut and colour to a consistently excellent standard.
The only salon in my town that's considered 'high end' is overpriced and I hear a lot of complaints.
Good luck
Vic x