I have read that port forwarding exposes your computer to security breaches. Does port forwarding a port on one computer expose other computers in the network as well? 


Question: Can't ping host in OpenVPN Site-to-Site VPN
Answer: It appears that even though you seem to have a "push" option in the config file for firewall2, there is a syntactical problem with it:

May 24 10:43:08 openvpn[7489]: Options error: Unrecognized option or missing parameter(s) in [PUSH-OPTIONS]:1: 112.202.103.45 (2.0.6)


Once this is fixed, you should have routing through the tunnel, which will give firewall2 access to machines on the other end of the tunnel.