when you configure the virtual server ( port forwarding) function, you can choose the interface to be WAN2 or WAN2

Set the URL filtering mode as Keywords

reset all the devices and re-configure them. you have to provide more information to get more usfull suggestions

it's impossible to send data over WAN2 and receive data over WAN1. to configure WAN1 for HTTP and WAN2 for FTP&Email. You can use the function of Policy Routing, port 80 (HTTP) go to WAN1, port 21...

you may got a windows server or other RRAS with security settings at site B, If so ,you have to do some configurations to let your server be access to your VPN tunnel

Go to the Firewall--->Attack Defense and un-check the Block ping from WAN