My "3 unit multifamily" unit appraised as a "2-unit" multifamily

[Samantha Robbins]

I recently purchased what is being marketed as a 3-multifamily unit. The layout is a residential single-family home that has been subdivided into three units consisting of 2 x two bedrooms and 1 x a one bedroom that is located in the "basement" of the house. It has a separate walk-out entrance, a gas heater, a kitchen and windows and has had a tenant residing in it for 9 years. According to the appraisal however, this is not an apartment but rather just a basement.

My questions are these:

1. If it is zoned as a 2-multi family, can I still LEGALLY rent all 3 bedrooms out?

2. What is the difference between the two zoning codes? And how do do I change them if I want to zone it as a 3-multifamily?

3. Is this something I can challenge? I.e. is this something that only this specific appraiser might think is a 2-family unit where as another person would consider it a 3-family?

Any insight anyone might have would be appreciated (especially on the first question)- I thank you in advance for any of your responses!