Plan to Emei shan and Leshan in May 2018

Hi
My trip will start from 26-28 May 2018
26 I will travel in Chengdu and 27 and 28 I plan to go to leshan and Etmei
and go back BKK around Mid night of 28 so I need your suggestion as below
1.we should go emeishan or leshan first
and how long to travel each place?
2. if we take high speed train to leshan and Emeishan, we should book first or later is ok, is it crowded?
3. can we come back to Chengdu and travel some attraction first before go to airport? or we will not have enough time? we need to go teddy bear museum and Jinli street, is it ok

Thank you for your suggestion