I (as well as others) focused on your question about Lecithin...but you also asked about cocoa liquor. I was wondering if you knew what 'cocoa liquor' was?
Cocoa liquor is simply ground cocoa mass, generally at the stage prior to pressing to separate the cocoa powder and the cocoa butter. Sometimes this is called unsweetened chocolate, although unsweetened chocolate might also refer to the same stuff after it has been further refined to reduce particle size.
In any case, if you want a decent shelf life in a sauce, you are going to need to control water activity. Since you likely want to keep the water content high in order to get the right texture for a sauce, you need ingredients that will 'bind' this water yet keep things fluid...and these 'humectants' are commonly the compounds that you say you don't want to use.
I'd suggest looking more closely at the whole range of humectants, learn and understand their properties, and then look for acceptable humectants that share these properties. You already know that honey is very similar to inverted sugar; honey is arguably a better humectant than inverted sucrose, more like the dreaded high fructose corn syrup So perhaps a naturally sourced honey is acceptable where a chemically similar HFCS or inverted sugar is not.
Sorbitol is found in many fruits; perhaps a fruit concentrate is acceptable.
Finally, plain ordinary sugar will lower water activity.
Good luck!
Jon