"You could always swap the trigger assembly to the rifle you are going to keep." - krod47nw
That may or may not work. As with barrels, the relationship with the inter workings of the the Handi change from one gun to the next. While I believe a stock trigger assemble will work in most (if not all) other rifles, a trigger that has been worked on may not. I had a handi that I had worked on. I then tried to replace just the trigger/spring. It no longer would catch on the hammer. I ordered a spare hammer, just in case. As it turned out, I needed it. So now I was back to a regular trigger pull. I am not saying it will not work, but your carefully tuned trigger may be the same, may not be the same or may not work at all.
If it was me, I would work on the 308 survivor trigger and get it to where I like it. I then would not have to worry about if the barrel fit or the trigger assembly would work, but that is me - do as you wish. Good Luck and Good Shooting