So, by the time we get to the twist, all that evidence back in part 1 had led me to three conclusions:

1) Hans is (pretty obviously) playing Anna:

Hans, you were not going to say that you finish each other's "sandwiches". As if.

Also note his comments about wanting to find his own place, immediate willingness to move to Arendelle, the rapidity of his proposal, willingness to put up with being hit in the face without so much as a 'hey!', his claim to love 'crazy', etc., etc., etc. .

Hans is thirteenth in line at home.  Anna is pretty. Anna is nice. Anna is much, much closer to a throne than Hans is.

My interpretation by the time we get to 1:14:59 (the moment of the twist) was that his proposal was politically and dynastically motivated, not motivated by love (see also #3), though there is no reason to think he particularly dislikes Anna. In fact:

2) Despite this, Hans is basically not a bad guy; he likes Anna, even though he doesn't love her:

Remember when he fell into the harbour at 18:32 and smiled a goofy smile? there was nobody there to see him. His goofy smile is genuine. He gives out warm food and clothing (come on, be honest, he'd do a better job of ruling Arendelle than Anna, any day) to commoners. He treats prisoners - which is to say, people with no power over him and whom he does not need to impress (though, again, see # 3) - very well. Animals like him – he has no trouble calming Anna's panicky, runaway horse. And, up until this point in the film, he's been kind and physically gentle with Anna (see how he lays her on the chaise longue) and has consistently tried to defuse conflicts and avoid / prevent violence (see all his interactions with Wesselton, for instance). This is true even when the violence would have been both excusable and logical, like at the ice palace.

https://youtu.be/F4SD_-GKsCQ

Also, let's be fair, here – aside from Kristoff, the important humans in this story are all 19th Century European Royalty. Contracting a marriage for political and dynastic reasons isn't evil; it's prudent.

3) Hans is fascinated by Elsa:

The very first time he talked to someone who knew Elsa (Anna at 17:00), he's warned off from Elsa. She's presented in Anna's speech both here and in the opening dialogue for "Love is an Open Door" as an impenetrable wall. Anna gives the impression that getting close to Elsa is virtually impossible. Nonetheless, at their first meeting, Hans is impressed by Elsa's use of ice powers. I direct you to his facial expression at 27:34, when he reacts to Elsa's public use of her powers. This is a man who looks like he's had some kind of revelation.

https://youtu.be/AiX-WvMNDPc

From that point on, Hans displays more interest in Elsa than in Anna. Between the end of the scene at 27:34 and the twist at at 1:14:59, Hans interacts repeatedly with Elsa and not at all with Anna. This adds up to 40% of the total run time of the 109 minute film – but fully 80% of the time between Hans' first appearance (at 17:00) and the 'twist' (At 1:14:59).

During this time, Hans:

*Defends Elsa to Wessleton - twice (just after 29:37, at 50:40).

*Displays an interest in and is impressed by Elsa's ice powers (again, the look on his face at 27:33, but also the question he asks Anna at 29:37 - did she know about her sister's powers - his awe upon seeing the ice palace at 1:09:37, his disappointment at 1:20:50 when Elsa admits she doesn't know how to bring back summer, etc.)

*Even though Elsa's an obvious danger to Arendelle, Hans orders that she should come to no harm (1:09:37)

*Hans twice tries to reason with Elsa and encourage her to be a better person, once to prevent her from committing murder (1:11:47, where he tells her "Don't be the monster they fear you are," - and note the wording used here, especially the use of 'they') and once to try to convince her that everything would be okay if she would only bring back summer (1:20:50)

*Hans saves Elsa's life, definitely once (at 1:12:02, when he deflects the crossbow bolt meant for her), but, possibly, more than once - Hans' line "I couldn't let them just kill you" is in response to a jailed Elsa's question "Why did you bring me here?" (1:12:50), implying that there may have been some discussion of simply killing her while she was unconscious.

By the time we get to the twist, Hans seems closer to, and more interested in, Elsa than Anna. In fact, on my first viewing, I had forgotten that Anna and Hans were engaged until she went to go get kissed.