... unfortunately, i've asked this Q of them and seen their facebook posts, and they've managed to contradict themselves on the possibility of individual releases.
the SCR boxset was supposed to be reissued on DVD-only, but this has never happened. my experience so far is that it's only happening when it happens, and any statement that says it definitely will has to be taken with a huge pinch of salt.
I'm sure they will get separate releases. I don't know about SCR (I know they mentioned the films wouldn't be released separately, reason I bought the set, but I wasn't aware they promised a DVD-only re-release afterwards), but at least for recent releases, whenever they announced a boxset, or a limited release, they have been upfront about what would be released separately afterwards, and what would be missing from it, and so far things turned out as they announced:
-they announced the films from the Camera Obscura: The Walerian Borowczyk Collection would be released separately, without the book, and they indeed released the films separately;
-they announced the same thing for the films from the Vincent Price in Six Gothic Tales by Edgar Allan Poe (with the separate releases missing just some of the content from the book included on the set), and they did release the films separately;
-they announced both The Long Good Friday and Mona Lisa would be released separately, without the bonus disc (the disc with a couple of interviews, and short film), and they released them separately;
-they announced Thief would be re-released without the 2nd disc (an exclusive for the first pressing), Society would be re-released in an amaray case, without the comic, among others, and they did good on that.
As for upcoming releases, they announced that:
-these two films will be released separately, without the book, after this boxset sells out;
-Deep Red will be re-released after the upcoming limited edition sells out, without the 2nd BD (with the so called "international theatrical cut"), and without the 3rd disc, a soundtrack CD;
-the 5 films from their Battles Without Honour and Humanity boxset will be re-released separately (without a 150 page book, and without the bonus disc with The Complete Saga, a compilation film featuring footage from the first 4 films).