Elder Sign is definitely fine at 2 (play 2 investigators each tho) it's a co-op so it scales well, box says 1-8 players, but it's really 1-4 (maybe 5 if you're desperate). Down time can be quite a bit with all the upkeep so 2 will actually feel better than 4.
Off your list in the pic? Flash Point/Pandemic are better co-op than Elder Sign, and King of Tokyo is a better yatzhee game. Elder Sign is a good core (it's a Knizia base design) but the theme is pasted on, and the game doesn't get really good depth without one of the last 3 expansions (Gates, Ice, Deep). Depends what you're really looking for, but Elder Sign the theme is all card text, which if you don't read, falls apart. If you're into Lovecraft, turn the lights down, play some spooky music, and make sure to read each card out loud as you play; it'll extend the game quite a bit, but it'll feel more alive.
Flash Point family variant is stupid simple, and I'm not sure I'd play it more than once to learn, unless I'm playing with small kids. The full game however has the ability to scale difficulty up/down really well, there's a lot of knobs to turn for complexity, and you don't NEED the expansions, but a single map pack for $10-15 gives a lot of variety. I always recommend it over Pandemic, not because it's a better game really, but because it's parts are more modular (play with just roles but no ambulance for easy, add extra hot spots/hazmat beyond what's called for if you want it to be Ghost Stories hard) and the dice makes it less predictable than Pandemic, so your strategies really can't be "perfect".
KoT is just the perfect dice chucker; push your luck, not a lot of options to cause AP, and fast; not a lot to be said about it, since the game is so straightforward, which is prolly why it gets more play than KoNY
Everything in your pic is good, recommended for casual gaming/2p. I'd skip Imperial Settlers, Hellas, Blood Rage til you know her likes/what works for you both.