Of Richy and DCL it's a weird one.
Richy is the guaranteed solid return, DCL is the riskier but higher reward if it goes well in terms of keeping.
I think if you are willing to sell Richy, then for a big fee you have to be willing to sell in our situation the one whose actually the riskier to keep (that injury just has me worried as hell) yes he's a year more on his contract - but DCL will devalue more than Richy will in a year's time if that injury reoccurs.
Sell both and trust in a really harsh rebuilding year by bringing in younger players scattered with a couple of more experienced ones with the right attitude.
Deli, Gordon, Patterson and Godfrey for me are big determiners how well we do in such a situation as all four have the potential to really contribute