Seriously, I've looked on the wiki and done everything it says I needed to do to get Gannon to give me the Remnants quest. He wont give it to me, I've started a new profile and got E-DE because the wiki says if you have E-DE in your party when you recruit Gannon he will give you the quest immediately so I'm working on the Followers getting to like me better, which is hard without my high level stats (oh speech how I miss you) and no doctor has Fixer for sale.

Any suggestions for my pre-existing file?

You need to reach a certain point in the main quest before the second quest of his starts.

I also wanted to do his quest. It's not possible until you are far in the main quest, sadly. Been reading the same about the ED-E thing, but it's false or just not properly written somehow.

Is there a mod to fix this?

Possibly, though it wouldn't make much sense.

On a house/yes-man play through I didn't get his quest until immediately before hoover dam. :mellow:

I hoped for something like "when you need a favour, call us" leaving them on a cliffhanger until I commit to someone and come to them again asking them to move to help that faction.

We sort of already do that with the Kings.

I'm at the part where House tells me to destroy the BoS.