Is it hard to reassemble all parts from broken logic board to a new?

But it is possible to replace all of the components to a new one, right?

possible yes, but not even the best at microsoldering would go through the hassle, plus if you have never done microsoldering / reballing ic's then don't attempt it as its not easy. liquid damage can be as simple as 1 capacitor being blown to corrosion under a bga ic. people that do this repair can check to see if there is shorted lines. you could be putting bad components onto another board and not know it and still be stuck in the same or worse situation