So Ennis and Jack would be a good combination??
Always.
I know there's been discussion before about whether they would actually get on if they lived together 24/7, not just a few days here and there each year, but I think they would. I think their characters balanced each other well, and as we saw from their time up on the mountain, they could intuitively 'read' each other (probably Jack more so than Ennis, always knowing the right time to lighten the mood and draw Ennis out of himself), and worked well together as a team, and I think both those things would stand them in good stead for a long and happy relationship.