Adding 1/2 Bathroom.........

i need to know, what is "standard" stub-in (roughed in) heights for vanity drain and water supply.

standards

Every plumber has his own "standard" height, and even those may be changed if the conditions in the wall require it.

You can rough-in the lav waste at:
18" for 30" counter
20" for 32 counter
Water supply can be roughed at the same level.
Most of the time, I use a strip bar to hold the stub outs and set the supplies slightly higher than the waste line.