Problem is here, I don't know how I can make Wheatley speak to player AND doing his animations same time(like lip syncing). So do I have to do it with prop_dynamic + ambient_generic or is there any easier way? Im not very happy to shove animation after animation when adding captions. Help is appreciated.

Me i made it with ambient generic + sequences of the core
But I don't know if we can make it by another way
I don't think so

You could always decompile the maps with the lines you want and see which animations they used, but there's definitely no other way.