there's some planning that needs to happen and some deadlines and targets you need to pay attention to but what you're describing is a very common scenario from a 1031 perspective..Perhaps the largest issue is that of the current state of financing for a multi-family mixed us property.  

Most commonly with Fannie Mae and Freddie Mac at least you cannot resell the property for more than 120% of the purchase price within the first 90 days.

Although in the lease we didn't mention how to terminate the lease early from the tenant's side, I think it is a common sense for them to let us know in advance if they want to leave early.

Starting small and learning the business first...seems that is common advice from most.

The first year was a lot of learning, trial and error.

Most of the headaches come from bad tenants, and they are far more common in C class properties.

Sometimes you can look at stats all day, but common sense still needs to play a factor. 

Common areas of the buildings have been all updated 2014 seller bought in 2012 for very close to $2.1 and that is what he will sell them to me under contract. 

It does not account for if a complex has owner paid utilities or some other high and less common general expense.I don't find it very useful at all to evaluate 50+ unit apartment buildings across the country as there are just too many variables.

It is not common to pierce the veil, but it can be done in the right circumstances.