Can I replace multiple NPN transistors with some kind of IC?
The ULN2003 Arrary contains 7 darlington transistors connected with common emitter. 



There is even a base resistor included.  You could choose which voltage level you desire, such as ULN2002,  2003 or 2004



EDIT #1 :  as pointed out by Peter Green, the saturation voltage (Collector to emitter voltage) when transistor is on is higher with Darlington than with a single transistor.
     Where typical transistor saturation voltage might be 0.3 to 0.8 volts.  The ULN2003 saturation voltage can be from 1.1 volts to 1.6 volts. Resulting in significantly more power dissipation of a single transistor.