Please put a copy of what you get from uci show network command.
You need to configure the L3 configuration which goes to wan/wan6 interfaces in LUCI, something like this:
network.wan=interface
network.wan.device='wan.35' # if the internet VLAN ID is 35, some operators offers or give you an option to leave it untagged so in that case just leave "wan"
network.wan.proto='pppoe'
network.wan.username='youruser'
network.wan.password='youpassword'
network.wan.ipv6=1 # get IPv6
network.wan6.device='@wan' # the "@" points to the l2 interface in which the l3 "wan" , interface is running, in our case the dhcpv6 protocol should run inside the pppoe tunnel which it will be named wan-pppoe and run over the "wan" ethernet iface.
network.wan6.proto='dhcpv6'
So, to set and apply this you can try:
uci set network.wan=interface
uci set network.wan.device='wan.35'
uci set network.wan.proto='pppoe'
uci set network.wan.username='youruser'
uci set network.wan.password='youpassword'
uci set network.wan.ipv6=1
uci set network.wan6.device='@wan'
uci set network.wan6.proto='dhcpv6'
uci commit
service network reload
If you have 0B/0B in Tx/Rx probably your VLAN is incorrect. Try just with "wan" no "wan.35" if that at least start to count. As I commented previously:
# if the internet VLAN ID is 35, some operators offers or give you an option to leave it untagged so in that case just leave "wan"
Without a VLAN tag assigned the Tx/Rx count should to increment, having success on the pppoe stablishment or not.
You can install tcpdump to show the traffic on that interface.
I do not think that the problem is the mac address spoofing here, or at least is not the only problem. You need to see traffic first on the interface. But anyway, to spoof the MAC Address you can do:
uci set network.wan_port=device
uci set network.wan_port.name='wan'
uci set network.wan_port.macaddr='xx:xx:xx:xx:xx:xx'
uci commit network
service network reload
You should refer to "wan" L2 interface, no "eth0", eth0 is just the ethernet switch and won't work. In your L3 "wan" interface says clearly network.wan.device=wan and if you run an ifconfig command you will see the "wan" interface there.