Here are the commands you need to schedule to connect/disconnect CN1 and CN2 in task scheduler

rasdial CN1 "username" "password"
rasdial CN1 /DISCONNECT

rasdial CN2 "username" "password"
rasdial CN2 /DISCONNECT

You need to assign a fixed IP to LAN card which is connected to DSL and then create a bridge connection between two ethernet cards on your main PC

For FTP access, you can install any 3rd party free FTP server or install FTP addon by MS itself. For other usages like proxy, media server etc ... let other members suggest

For DHCP, enable DHCP server in your main router that's all