They can't be twins, because they've got different patronyms. Hans Kristensen is son of a Kristen, and Hans Rasmussen is son of a Rasmus.
I don't quite get the relationships here, but it seems like Hans Kristensen is the son of Kristen Hansen b. 1842. Hans Rasmussen is probably the son of Rasmus Waldemarsen b. 1837.
The 1891 census is written on one card per person, and apparently the Hamre households have been given quite a shuffle. There should be a family overview somewhere, but I've never worked much with this census and am not sure how it's organised.