OP - you forgot a bunch of Fed Ex forms for all the stuff you're going to ship home.
I did a 6 week trip of the UK and Ireland with about 20 lbs per person with full camping gear and it all fit into 40 liters of panniers plus a handlebar bag. Current bikepackers would look at my set up and be amazed at how much extra I had.
Change your methodology - Start with the volume you have to work with and work backwards from there (and ditch the huge duffle bag). Get synthetics that dry fast and you can wash them when you take a shower - that eliminates all the duplicate sets beyond 2 of everything. Synthetics also tend to roll up pretty tight. Everything has to be dual use, plan on layers for cold, not bulking single layers, and keep it simple. On your coldest day, you should be wearing everything you have if you did it right.
You can't take fuel canisters on the plane. You can buy fuel canisters all over Europe. We were most recently camping in Norway and Iceland and had no issues finding the screw on kind. For two of us, we tend to use just over one canister for about every 10 days if we're careful. The stove I have - Optimus Optifuel - will use gas canisters or even unleaded gas. So I don't worry about fuel.
J.