Regarding that high pressure fuel line from tank to filter. If you undo it again and slide a length of plastic / rubber hose well along it and tighten the union again. Then slide the plastic hose back right over the union.
If the union does leak it won't spray a fine mist out just ready to be ignited. It will just drip to the ground so you will know to fix it.
Good progress. Thanks for writing it up for us.