Thank you for interested in OS Services Booking, regarding to your question, i would like to answer as below:
1. OS Services Booking supports custom fee fields, you can add custom fields with additional cost, and customers will able to select extra options for their requirements.
2. OS Services Booking supports Deposit payment, it's a percentage of total order amount that customers must pay to activate their order.
In OS Services Booking, we have layout called: Default Layout, in menu parameters form, you can select specific service. By this way, you can create different menus for your existing Services.