first, your title..."best digicam for under 10k" largely depends on what your definition of the best...
wide lens? long lens? hotshoe flash? waterproof? touch screen?
now for graduation events purposes...NONE of these you listed are enough...
why? you need powerful flash to cover long range...you need long lens for capturing the subject receiving diploma etc....none of these have that...
ive tried all these cameras you mention at one time or another...we sell these at gizmo...
heres the rundown:
Samsung ES60 is so slow i could take a nap between takes
GE G3wp slower than the other GE and low Q lcd but waterproof
GE E850 images doesnt look great on the lcd either but not bad for a budget cam and wide angle lens
GE G2 smaller and lighter but terrible focusing speed and accuracy
E850 would be my choice on the list for image,widelens,and speed and G3wp for being waterproof it be great for the coming summer