I think I would be a bit more cautious with multiple MELs.
For a single MEL, the MMEL guru committee has brainstormed the effects of the U/S on certification and come up with an equivalent risk level by imposing appropriate restrictions.
Can I ask you to quote where in the typical MMEL there is any cogent indication that the intention is to cover multiple failures ?
A crew refusing an MEL permission is the last in the line of defences .. the MMEL doesn't address the detailed specifics of TODAY's flight .. weather, alternates, crew fatigue, etc. etc. ....