I am monitoring 8 circuits on an Uno board as digital inputs. 7 use internal pullup resisters and 1 uses an external pulldown. If each circuit I am monitoring has ~2k ohms resistance when closed, will this somehow create a problem or damage the board? (as opposed to monitoring circuits that are ~0 ohms when closed). Thanks.
As long as the voltage is within spec your fine with the Arduino. But I can't say anything about possible problems the load the Arduino (and pull up/down) may cause. Don't know what "the circuits" are.
Do they measure <1.5V when low, and >3V when high? Then you’ll be all set.
Look at them as setting up a voltage divider with a 30K internal pullup.
5V2000/(30000+2000) = 0.3V. Good!
5V30000/(2000+3000) = 4.7V. Good!