Is there a way to add enhancements to appointments using MarketPress or discount for multiple appt?

I have a number of enhancements available for services that are currently in Appointments+. I'm currently working on an integration to utilize MarketPress and Appointments+ to allow for multiple service appointments.

Is there a way to allow enhancements or some sort of variation to the services during, or before checkout?

For example, a client would book an appointment for a 60 minute massage, but rather going directly to the shopping cart, a pop-up or something appears allowing them to add enhancements, such as cupping or hotstone, or when in the shopping cart, suggested enhancements appear for certain services.

I have different enhancements available for different services, so their suggestions or appearance would be conditional.

For example, massage services have the following enhancements: cupping, hot stone, aromatherapy, and foot scrub; while facial services have the following enhancements: eye treatments and lip treatments.

Additionally, is there a way to add an automatic discount for someone who books multiple appointments? Say, book 2 appointments, and the third one is 30% less? Maybe not automatic, but a coupon code that would conditional on the number of appointments that are in the cart?