HI DimitrisS,
Thank you for your purchase.

1.

This feature is called Front end booking cabinet for customers, and that is the next major feature that we are working on.

2.

Yes we have API Routes for the Amelia app, but most of them are protected depends on of the permissions that is set in WordPress Accounts. You can check those API Routs in our free version of Amelia. Amelia Lite is a free WordPress booking plugin that allows to set up a fully-featured automated WordPress booking system on your website. It is a handy tool for small businesses and individuals that depend on stable appointment-booking processes. You can download it from this link.

When you download Lite version you can find all API Routs in this file ../wp-content/plugins/ameliabooking/src/Infrastructure/Routes/Routes.php

Unfortunately we don't have hooks (action and filters) at the moment. What we have is a few JS hooks that is triggered depends on the view:

window.beforeAddToCalendarLoaded()
window.beforeBookingLoaded()
window.beforeSearchLoaded()
window.beforeSearchFiltered()
window.afterSearchFiltered()
window.beforeConfirmedBooking()
window.beforeCatalogLoaded()
window.afterSelectCatalogCategory(object_category)
window.beforeCatalogCategoryLoaded(object_category)
window.beforeCatalogServiceLoaded(object_category, object_service)
window.afterSearchActivateService(object_appointment, object_serviceActive)
window.afterSearchGoToSecondStep(object_appointment, object_serviceActive)
window.afterBookingSelectDateAndTime(object_appointment, object_serviceId, object_providerId, object_locationId)
window.afterBookingSelectService(object_appointment, object_serviceId, object_providerId, object_locationId)
window.beforeConfirmBookingLoaded(object_appointment, object_service, object_provider, object_location)
window.afterConfirmBooking(object_appointment, object_service, object_provider, object_location)

JS files are modified (minimized) in public version of plugin (in our development environment is accessible), but unfortunately I can not send you our source code because that is the policy of our company.

All those files that have extension .vue are compressed and minimized in JS files that is very hard and not recommended modifying. So in order to add some other features you can unminify the js and customize it.

3 and 4.

Sorry to disappoint you but unfortunately something this is not possible to achieve with the plugin built in features at the moment.

Best regards.