Although it would be tough to turn down the HC job of a storied team like the Giants - playing in the biggest media market no less - I actually DO think McDaniels and Patricia should remain here (especially if there's any question about working with a GM they aren't in sync with)
The thing about both of them - as long as BB and Brady are here, and they are Coordinators, they BOTH will continue to have advancement opportunities. Moving to the wrong team at the wrong time and they can find themselves out of a job in even a year - and in Josh's case, two strikes and he may be out forever.
So do what Scarnecchia did - settle in for the better quality of life as a devoted Coordinator until such time that BB opts to give up HC, become President and you get your chance to be HC here in an already well established system - effectively YOUR system that you've adopted as a BB prodigy.
I'd say McDaniels has the better shot over Patricia (IMO Patricia accepted a life appointment as a Patriots coordinator when he wore the Goodell Bozo shirt - and I don't think he even WANTS a HC job - though again, it's his for the taking elsewhere anytime if he does.)
That's best for them - they need be in no rush and the ultimately the best career move could well be to just remain here until their chance comes, as it sadly will one day