Explanation/Reference:
Explanation: Clientless - Users connect through a web browser and use HTTPS connections. Clientless solutions usually supply access to web-based corporate resources.
Reference: https://sc1.checkpoint.com/documents/R80/CP_R80BC_Firewall/html_frameset.htm?
topic=documents/R80/CP_R80BC_Firewall/92704

There is no need to generate new license in this situation, just need to detach license from wrong Security Gateway and attach it to the right one.

Explanation
More than one administrator can connect to the Security Management Server at the same time. Every
administrator has their own username, and works in a session that is independent of the other administrators.

Explanation
Secure Internal Communication (SIC)
Secure Internal Communication (SIC) lets Check Point platforms and products authenticate with each other.
The SIC procedure creates a trusted status between gateways, management servers and other Check Point components. SIC is required to install polices on gateways and to send logs between gateways and management servers.
These security measures make sure of the safety of SIC:
Certificates for authentication
Standards-based SSL for the creation of the secure channel
3DES for encryption
References: