Possible Rushed?

Hi, I understand that the minimum connecting time is 160mins from domestic to international - however in terms of best timing for my schedule, I will only have 2 hours from the expected arrival of my plane from Dalian into Beijing, to the departure of my flight to Singapore. To expedite my movement I am only travelling with a carry-on bag so that I do not have to wait for baggage claim. Is it possible to get through customs on both sides in time?

Also, my flights are around the midnight hour - which I understand the shuttle buses do not operate then - how then do I best get from Terminal 2 to Terminal 3?

Thank you!