Difference Between Townhouses Multifamily Vs Apartment building

Hey Guys, 

What is the difference between Townhouses Multifamily Vs Apartment building ? 

1. Are they getting the same evaluation metrics (NOI) ? or different Metrics ?

2. what check list should be asked when first walking the property ? 

3. Any things to watch out for ? 

little about the property 69 units (1 module of 3/2.5 and 1 
car garage 1600sqf+ approximately ) 

4. Is it enough to qualify for Dscr loan product  ? 

5. Are there any Multifamily Mentor groups / Meetups I can attend ? 

Thank you