The private apartment of Nicholas II & Aleksandra Fyodorovna was not the same private apartment or apartments of Alexander II & Maria Aleksandrovna. Nicholas & Aleksandra's private apartment occupied what was once the private apartment of Nicholas' great-grandmother, Aleksandra Fyodorovna, the wife of Nicholas I. Their decor & decorations replaced hers, which had been designed principally by the architect Bryllov among others. I have, somewhere, a picture of the dressing room from that apartment, and it was very beautiful before it was destroyed, with an order of Corinthian pilasters lining the walls.
Alexander II & Maria Aleksandrovna occupied different quarters in the Winter Palace. Their rooms were located farther along in the same wing, on the same floor, beginning roughly where N & A's rooms stopped, and continuing all the way to the end of the building. If I remember correctly, the "family" rooms were the suite of rooms facing onto the Palace courtyard. The dining room was the room in the exact centre of the courtyard facade. I think this is the room the assassin from "People's Will" planted a dynamite bomb beneath in an earlier attempt to assissinate the Emperor. He survived the attempt, because he was in another room when the bomb went off, but I believe something like a dozen others were killed.
Alexander's wife's rooms began at the Palace Square end of the building and contiuned onward until they ended with the Emperor's rooms. There isn't a plan of that section of the palace on site, so I will walk you through the first part of her rooms verbally. Beginning at the SW corner of the Palace is the Golden Drawing Room, followed by the Raspberry Drawing Room. These 2 rooms take up the entire breadth of the pavilion, where the pavilion at the other end of the Palace (N & A's apartment) is divided into 5 rooms. Turning the corner, the facade recedes. The first room here is the Empress' boudoir. Next this, forming a pivot between the corner pavilion & the long march of the centre part of this wing of the Palace, marching down to the North end, where N & A lived, is the Empress' bedroom. I presume her more private & intimate rooms were behind the bedroom, in one direction or the other. The decor of the principal rooms of the suite, which is by the architect Stakenschneider, is largely intact, although these rooms were, the last I knew, used for display.
Just beyond what was once Nicholas' Private reception room, there is a staircase, which serves to separate the last Imperial Family's private rooms from those of Alexander II. Going up this staircase to the next floor, it pretty much debouches onto a long corridor, which was once known as Freylinskiy Koridor [I may not have transliterated that correctly], the "Corridor of the Maids of Honour". In the rooms along this corridor -- although I do not know whether it was on the courtyard side or the outer, Admiralty side, or both, Alexander installed the Princess & their children. Logically, it would seem that the Pss' rooms would come first, and that the children's rooms would be beyond hers, but adjoining them. This would put them near enough over the private rooms of the Empress & in the vicinity of her bedroom, that she quite possibly may have heard the "noise" from the children on more than one occasion.

KEY:
A-P = Nikolai II & Aleksandra Feodorovna's private apartments
A II = the private apartments of emperor Aleksandr II
MA = the private apartments of empress Mariia Aleksandrovna
1 = the First Reserve Apartment
-- (formerly the private apartments of Mariia Nikolaevna & her
husband, the duke of Leuchtenburg)
-- (note: the 5 large rooms facing Palace Square were later
diverted for use as the 5 Military Halls, housing a collectiom of
military paintings)
2 = the Second Reserve Apartment
-- (formerly the private apartments of the young grand dukes
Aleksandr, Vladimir, Serge & Pavl Aleksandrovitch)
3 = the Third Reserve Apartment
-- (formerly the private apartments of the young grand dukes
Nikolai, Mikhail & Konstantin Nikolaevich)
** -- the Fourth & Fifth Reserve Apartments were located on the ground floor beneath N II & AF's private apartments and part of A II's.