Bridge mode without a modem

Hello everyone. I have spent many hours these last few weeks trying to figure out how I can get set up in bridge mode.
Right now, my ISP has given me an ONT box, which turns fibre into an RJ45 ethernet cord. I have been trying to treat it as a modem, but the unit does not do PPPOE authentication, so I don't know if updates will work.

Right now, I have been trying this setup:
ONT box -> AdTrap -> iGuardian -> Asus router (doing the PPPOE)

I have ALSO tried ONT box ->ISP modem/router all in one -> AdTrap -> iGuardian -> Asus router

As you can see, I've backed AdTrap on Kickstarter. It is similar to iGuardian, being an adblocker box.

I've tried 2 methods:
both AdTrap and iGuardian working inline
and
Quad NATting (and forwarding ports through each layer). So my ISP router is 192.168.0.1, my AdTrap is 1.1, my iGuardian 2.1, and my Asus router 3.1 However I am unable to get the internet connection to work as well coming out of the router.

Can anyone please help me figure out a good way for me to set up these 2 boxes inline, without a modem?
I was thinking maybe I can buy a ddwrt router and put it in bridge mode, and treat that like a modem and do PPPOE on it? But why wouldnt my ISP router work instead of a mode? (It doesnt have bridge mode, so it was router -> router, instead of modem -> router.

As well, it seems the captcha code for signing up on the forum only works in IE, and making a post only works in IE too, and not in chrome or firefox.

Thanks,

Just a thought... try to remove all irregular variables.

Try ONT box --> eth0 Shield (bridge mode) eth2--> WAN in Asus Router (pulling external IP, serving internal DHCP),  without AdTrap just yet.

You'll need to plug Shield eth1 into a LAN port on the Asus Router. In Bridge Mode, Shield doesn't provide DHCP to the LAN, your Asus Router will do that. You may need to manually assign/reserve the x.111 lan ip in the Asus for the shield MAC for eth1.

Then, you'll need to boot things in sequence: 1) ONT box, 2) Shield, 3) Router and hubs. You should see the Luci interface come up on your LAN at x.111 eventually, whether you have internet or not.

Log into Luci using 'Admin' as your user id and your password. Note that when accessing Shield via SSH or telnet your user id is 'root', with same password.