This was a good thread on the topic: Park does not meet current setback and spacing ordinances
I’d suggest you see if you can fit a 16 wide too - they feel so much bigger than a 14 wide inside and are more desirable. I expect the city would want you to use the same materials that are out there already, if not more. Additionally, you’ll probably have to upgrade to 200 amp panels from the 50’s that are probably out there today. One final item - if you’re replacing a bunch of 1BR homes with 3BR homes make sure your utilities can handle the increased overall occupancy.