1) Simple webapp for user login/signup. A user can have 3 roles(admin, user, client). If the user has more than one type of role, then you should ask to disambiguate. You need to use AWS cognito for this(I am okay if you are willing to learn). The redirection happens based on the role of the logged in user. You can create dummy webapps for redirections.
2) The webapps are to be developed in react + spring-boot package. You can see this example: [login to view URL] It should be pretty simple.