Commercial Real Estate for First Timer in Philadelphia?

[Achillina L Rianto]

My husband and I have been looking for a multifamily unit within walking distance to our current home that we will use both as an inlaws suite and an investment property. All of the multiunits within our budget that is available near us currently have commercial store front on the first floor with apartments above.  We are quite comfortable with the idea becoming a residential landlord (although we know that it will come with its own learning curve) but we have very little knowledge about commercial real estate.  Should commercial real estate even something that we should consider or should be rule it out altogether?  

Should we consider changing the zoning of the commercial unit into 2 separate apartment units?  through some research, I found that rezoning a property in Philadelphia is time-consuming and costly so we hesitate.

For some background, we are looking within few miles of zip code 19147 (within 20 minute walk), budget under $700k, quadplex preferable or potential for a quadplex, will put 20% down.  Thank you in advance for any input.