Answer:
They all have to do with counting.
国 KOKU, kuni - country - counter for countries
屋 OKU, ya - roof, dealer - counter for shops
夜 YA, yoru, yo - night - counter for nights
星 SEI, SHOU, hoshi - star - counter for stars (rating hotels etc.)
幕 MAKU, BAKU - stage curtain, act, shogunate - counter for play acts