WORDPRESS PLUGIN CUSTOMISATION

We have purchased a plugin called TourMaster and we are looking for some customisation in the plugin to make it fit our business.

The plugin website is https://goodlayers.com/tourmaster/

We require the below custom work;
Pricing - I am looking for a pricing structure for room based option where there is two prices for children. For example the pricing;
o Adult/Base price is £1,000
o Child price is £750.00
o FIRST child if two adults is £500

Payment Modal – We would like this payment modal integrated as the only payment method.
https://demo.trustmytravel.com/modal/

Deposits – we charge a fixed fee per person for deposit so would want the system changed. Currently it is done on a percentage.