What are the consequences of putting down a false ethnicity on your application?

Just leave race/ethnicity off.
As for “speaking a few words of Urdu”… Seriously, leave that off unless you have an externally-validated certificate of proficiency worth mentioning.
Finally, run the NPC on many colleges. It’s fun to think of dream schools - but the real work is finding safeties and matches you like and which your parents can afford.