Best practices and questions about functionalities

Hello there ! I have a few questions about Keycloak !

First of all, is it possible to custom UI while deploying using docker ?
Also, is it possible to add dynamic b2b management ? Meaning a user can register on my webapp for example, and when I approve it’s request, a new client would be create via http request on keycloak realm, to allow client to access it’s personnal dashboard and use my api(s) on it’s own app / website

Last but not least, is there anyway I can find documentation about specific endpoints and everything to get ready and implement keycloak to my nodejs api and react app from scratch ?

Thanks a lot for reading, hope you’ll be able to help !