https://www.prolinerangehoods.com/blog/cfm-need-range-hood/
You can vent both the gas oven and the stove separately. You have to buy high end appliances for that. I've seen them but can't remember.. maybe a Viking stove or something prosumer-commercial. Make up air can be a cracked window or a separate intake duct that opens up when the vent is turned on. Your local building code will have specific requirements.
You can duct a hood out of an external wall or even better out of the roof. If you go with a roof vent you can install the extractor fans in the duct in the attic which helps reduce noise if that's a concern. What you can do will depend on your specific kitchen.
I have found that the stove top is worse than the oven for emissions. The reason is that my exhaust hood is under-powered and it's a microwave/exhaust combination that doesn't extend over the entire cooking surface. So I would advise a hood larger than the stove top itself, install a larger duct and I would overestimate the CFMs required. If you get a multi-speed range hood then you can adjust it as necessary.
I actually think electric ovens are better combined with a gas stove top. Electric ovens though do have a tendency to fail at inopportune times (e.g. the holidays!)
I don't have counter evidence on hand but assuming the oven is vented outdoors, my understanding is that a hood should be relatively low-powered, not high, in order to then capture emissions from the stove top. It should be a function of size, height from the stove top, noise constraints, etc.