Multi-zoned property as commercial/residential? Convert or as is?

[Michael M.]

I own a two family house in the Bronx that is in a commercially zoned area.  Every other building on the street is a large tenement style building with a ground floor business (restaurants, bars, cell phone shop, bike store, etc).

1. Would it be possible to use the ground floor apartment as a commercial space, say a store or a restaurant or a bar AS IS, or would the space itself have to be altered/converted for that to be legal?  I'm imagining some type of bar/ store that is in layout of the house as my own personal business.  I see this all the time upstate and in rural areas... could this be legal in NYC?

2.  Do ground floor commercial spaces make more/less/same money as residential?  Would I be better off converting the ground floor to commercial and renting it out as a commercial space than in its current layout as an apartment?

3. Is this worth more than a regular residential property for resale purposes?  Do developers want something that is zoned commercial/residential, or is that not a factor?

The specific zoning is R6 with C2-4 overlay.