I am trying to help my dad who is retiring this summer after 40 years of owning his own dental practice. 

Is this a legal and acceptable practice?

of 2008 put some limits on the practice only allowing you to exclude gain from the actual time you spent in it as a primary residence.  

Practice all you can on many things as you can and concentrate on things that will help you hear "yes".  

So many practical reasons to invest locally when starting out, but the cost of entry is so low I can't ignore the opportunities...

Except:For cases limited to the Hennepin or Ramsey County Housing Court, Rule 603 of the MN General Rules of Practice may allow a principal (or agent) of the corporation or LLC to sign court papers or appear in court on behalf of the business entity.

I'd tend to steer people away from the practice rather than coach on how to do it -- there are better business models that are focused on adding value that I'd rather see people embrace.My meetup is really about sitting down and talking nuts and bolts, and, while I am agent, property manager, contractor, etc, I don't host the meeting to sell you anything nor do I charge anything to join, which many other meetups do.

Not  totally ready yet to purchase, but thought it would be a good practice. 

Also - would it be bad practice to moderately increase the rent (they haven't had an increase in about 3 years and their yearly $/sq ft is slightly below the market).  

I would like to begin looking into single to fourplex residential locations to invest in and want to get practice on analyzing deals.