Alright, managed to do risk 20! It managed to be less stressful and took less time than the risk 18, mostly due to me getting better with timing Angelina and Eyjafjalla's skills and not having to rely so much on Lappland's skill 2 activating (and also not doing it an hour before week 1 finished). I also put a couple into Saria's skill 3; like @whatayuri said, it may be niche, but it's still incredibly useful for these events.
My risk 19 run. After trying out the different Week 2 contracts, I ended up just settling for the "Enemies +50% attack" contract since I wouldn't have to adjust my previous strategy as much. I also replaced the "Friendly units -60% defense" contract for the "Friendly units -30% defense" contract, just so the enemies don't hit too hard. I swapped out Ptilopsis for Warfarin; even though my Warfarin's only E1, her extra range was more useful here and her SP talent was probably more useful than Ptilopsis' considering pretty much all the enemies were dying in front of her.
For my risk 20 run, I decided to go back to the "Friendly units -60% defense" contract. In doing so I had to replace Warfarin with Silence, just to keep everyone alive. I also leveled up Saria a bit to help her survive the ninja enemies. Unsurprisingly this took me a lot longer than the risk 19, but it was still less time than my risk 18 run, mostly due to better timing of Angelina and Eyjafjalla's skills. It took more than a few hours and a lot of trial-and-error, but this Contingency Contract's definitely been fun.
As for other CC-related stuff, in the current CC event on the Chinese server there's a support contract that cuts down your operators' redeployment time. Combine that with fast-redeployment operators and Silverash's first talent, and you get this silliness.
Also, completely unrelated to CC, here's an Asbestos x Sora comic. Poor Asbestos lmao
