Macbook Pro 15, 2017 | Burned connector and no charge Is it possible to replace this two components.
(J4402, J3300) I saw some components on Aliexpress but I don't know anything about a motherboard.
or do I have to replace the whole logic board? 

Thanks for the help!
It is possible to replace components on a circuit board. It is expensive to get the tools and expensive in time to train and expensive to test the boards once repaired to be sure they are in spec. 

Realistically, for about 95% of repair shops (maybe 99.9% even) it’s cheaper to swap the entire logic board. Only Apple or the Factory that makes these in the first place likely get enough failed parts back to make it economical to refurbish and repair damage like that. 

Also, how are you going to diagnose and fix what caused the power overload? Once you repair the connector, there’s more going on than a melted part.