visit giant budha leshan & mt.emei,.late december 2012

Maybe Leshan can come first. As for your visit, here is my kindly suggestion and I think 2 days can be ok. You can go for other attraction on the third day.
D1, Leshan - Emei. then stay at Emei around
D2, climb and view Mt. Emei - back to the CD city

It's nearly impossible to climb to the summit of Emei and go back to the foot of it in one single day. For me, it needs 3 days. So I strongly suggest you go to the top of Emei by the tour bus which is at the foot of the Emei Mountain. After you have seen the view there, you can get the cable to the Half-Mountain and see the Wanniansi Temple and monkeys. About 3 hours walking ,you will arrive at the station Wuxiangang, then get the tour bus again to its destination. That makes a whole day. You should get up early on that day too.
And the 1st. day, you could follow the sugggestion of Alisa.