The bearings you require are
Front Wheel 6203-2RS CN or C3
Rear Wheel 6204 - 2RS CN or C3
Sprocket Carrier 6206 - 2RS CN or C3
RS is for rubber seals an CN is Clearance Normal and C3 is Clearnce code 3
The clearance is measured between the balls and the rings and you have C1, C2, CN, C3, C4, C5. There is aslo a CM clearance which is in and around the same clearance as CN and often used to reduce noise.
C1 has the smallest clearance and C5 the largest.
The possible heat (disk transfer) and vibrations (road surfaces and out of balance) the wheels would really necessitate CN or C3 specification, C3 being the most common aftermarket type
Since the bearing is a vital part in the bike, for your own safety stick with known brands.