Filing 2 Year's ITR U at the same time

I am planning to register as a SEBI registered research analyst, and I need to submit 3 years of income tax returns (ITR) as part of the application process. Can I file this year's ITR and two ITR-U forms at the same time (this month)? Can I submit ITR-U if my previous assessment year's income did not exceed the basic exemption limit and submit nil ITR-U without paying late fees?