So you will want to plan on some renovations in your other units and a little bit of lost rent.You will also need to provide fire walls/ceilings between all of the units.

Lenders have this firewall in place to protect themselves and make sure their borrowers have steady income.

The garages don’t have firewalls up to the roof to separate off the halves.

I renovated a 7,000 sq for mixed use building and had to fire wall each unit.

Today, many building codes require a firewall between two or more units.

A conversion  to MF today is not usually a novice activity. you have firewalls, separating electric, water etc. 

We also believe there is no fire walls to separate the "units".

. :)Ubiquiti edge router ~ $60 (Personally I would use an Untangle, now Arista, firewall and skip the router, but that is not as user friendly)Ubiquiti 4-port POE switch - ~$30Ubiquiti LR-AP ~$180 (Can usually find in a 5 pack for cheaper)Plus wiring, plus somewhere to house the switch closet (Doesn't need to be fancy, just needs power and to be dry, like @Michael Baum saidThis is just off the top of my head without ever seeing layout/walls/etc.

You'll need fire-walls, separate entrances, separate HVAC, etc.I bought a 1,100 SF house that was being converted to a duplex, each side with 2 bedrooms/1bath.

We found CDW everywhere, ceilings and supposed "firewalls" in the garage where there should have been 5/8 board, but wasn't.This isn't a complicated rennovation, just time consuming.