The games are gone from the Humble store now. Green Man Gaming still has SFC and Sayonara listed. Shun is no longer available to buy at all.
It appears that, for now, Sayonara+ is still up on the PSN stores, and 3DS Sayonara is still on the European/Australian eShop. As Piku said, though, they could be removed at any time, but the North American eShop release shouldn't be going anywhere.
Anyone wanting the PC versions of SFC and Sayonara should try Green Man Gaming while they still have the games listed, and anyone wanting to buy any other digital release of Sayonara that is not the North American 3DS version should do so now.