A. Yes, most firewalls are configured to allow outgoing connections from the computers behind them. If you use a software firewall then you may be prompted that the program is requesting permission to connect to the outside network or you may have to manually configure this.
A. The remote support session uses 256 bit encryption, the same that bank sites and major financial institution uses. The end user is in total control of the experience at all times and can end the session at any time if they need to by simply closing the program.