Replacing an electric range with a gas range
So far as I know, residential ranges and ovens do not require venting to the outside, only commercial locations (restaurants etc.). You might WANT to do so to get smells / cooking smoke out of the house, but it is not required. In that case, you can likely fit your over-the-stove microwave oven with a pass-through vent that would go through ducting and out the roof. DO NOT use the same venting you have for your utility room, those are different venting requirements and you do not want cooking grease venting into that room.
As to the gas pipe (although I agree, should have been a separate question), we cannot answer that from afar. Pipe size, pressure and requirements for the stove and oven are details that make a difference. Professional plumbers have calculation methods for determining that. SOMETIMES a cooperative gas utility will help you out with that because after all, they LIKE selling you more gas. If so, then yes, you can tee into an existing gas line to feed a new appliance. But be forewarned, if you have never run gas lines before and learned how to do it from someone with experience, it's not something I recommend for novices. Mistakes can be deadly.