Ask Mr. Smarty Plants

In part, you may to be searching for an answer that doesn't exist.  Although, the heart of your question seems to be getting at the difficulty - and ongoing confusion - created by the various plant naming systems devised over the past 200 years or so.  Insofar as that is the case, we may be able to shed some light on the various parts of your specific question. 

In every classification scheme we know of, the genus Cucumis is placed in the family Cucurbitaceae.  Therefore, if a species is in that genus, it is also in the same family. Because the classification system is hierarchical, any given genus must belong to a single family. In other words the genus, Cucumis, cannot not be assigned to multiple families. It is possible that a species formerly classified in the genus Cucumis is now placed in a different genus outside of Cucurbitaceae but we do not know what it might be.

As for the higher classifications, various taxonomists have devised different classification schemes that often reassign families to different orders.  In the APG (Angiosperm Phylogeny Group) classification system, for example,, the order Violales does not even exist and the family, Cucurbitaceae is placed in order Cucurbitales.

In an older classification system known as the Bentham and Hooker System (named for its authors, George Bentham and Sir Joseph D. Hooker), Cucurbitaceae was placed in the Passiflorales, while placing Violarieae (an older spelling of Violaceae) in order Parietales.

In yet another system of classification, The Reveal System (named for it's author Dr. James Reveal), Dilleniidae is a subclass of the class Rosopsida, while in several other systems it is placed in the class Magnoliopsida.  Some classification system, such as APG, do not recognized classification levels above order.