This is tough. Kamara for sure especially if Brees and Payton are still there. So it's really between Watson and Engram. I personally feel Watson is a stud and top 5 QB next year (maybe even top 3). Engram should be a top 5 TE next year, but it's uncertain to me how his target share will look with OBJ back. Then there's also the ACL injuries for Watson. That's 2 ACLs on different legs now. How will that affect him going forward?
So to answer your question, I would say Kamara for sure. If you can wait until after preseason next year to make a decision, that would be ideal. So you can see how Watson looks post injury and see how targets may be distributed on the Giants offense. Engram should see plenty of redzone targets for sure. Unfortunately, it's too difficult to make the decision now, but I'm leaning Watson with the assumption that his injuries won't hinder his abilities going forward.