The first one is called Witherwood Reform School by Obert Skye. You might have heard of Obert Skye from his other series about a kid who's closet is a mess and morphs literary characters in to one terrible character, like Harry Potter and Chewbacca, who become "Potterwookie". They are pretty hilarious and my students like them a lot. The Witherwood Reform School is a departure from those characters and situations and a leap in a series of unfortunate events. Two perfectly charming children, Tobias and Charlotte, have been living with their dad (a distracted and overworked but loving parent) and a completely horrible nanny (and how they can afford the nanny when their dad is driving a cab is a bit of a mystery). Tobias and Charlotte play a trick on the nanny so to punish them, their dad drives them to a deserted place and drops them off. He drives away but almost immediately turns around to get them but is involved in a terrible car accident which leaves him with amnesia. He has inadvertently left them at the Witherwood Reform School where kids are brainwashed into compliance. If your kids like books like a Series of Unfortunate Events or The Name of this Book is Secret by Anonymous Bosch or just about anything by Roald Dahl, they'll like this one too.
The second one I read was a fairy tale adaptation called A Grimm Legacy by Janna Jennings (not to be confused with THE Grimm Legacy by Polly Schulman (I liked that one a lot too). This one is a little confusing because there are four characters who start in completely different places and are thrown together in a place they don't recognize. They each appear to be playing parts in different fairy tales and right at the end, you find out why that is (sorry, no spoilers here!). The characters are all teenagers but none of the situations they get into are very adult (although there is some flirting and a gun makes an appearance). It seemed like the author was shooting for a YA audience but it read more like middle grade fiction. It was pretty compelling and there was a lot of action. The way it ended also gives you the idea that there is more to the story so it will be interesting to see where the series goes after this.