Thanks for your thoughts, halbert and yandj. I didn't realize that the cooktop would need so much space. I am not sure yet as to whether I want to give up cabinet space for an oven. LOL, mavia-2000. My range is still going strong. The fridge died and we replaced it with a Samsung SS. Since the dishwasher sounds like a plane overhead whenever I have to turn it on, I am considering replacing the dw and the range with SS. It is good to know that I might have sixteen years to figure out the cooking arrangement. What Wolf downdraft are you getting? Could I also use the Dacor or Wolf telescopic downdraft behind a slide in range? I have about two and a half inches between the slide in and the backsplash. I could hook it to the venting system that is already in place.

What exists currently is a fire hazard and needs to be changed regardless of anything else that you do. You cannot have wood directly above a cooking zone unless it's at least 30" above it. Overhead venting is always superior to downdraft. Especially if you want to convert to gas. A strong wind right at a gas flame tends to do funny things to it. Like suck it out. Overhead venting captures naturally rising steam, grease, smoke, and odors, and if you can have the correct ductwork added, gets all of those nasty things outside of your home. Because all of that stuff rises upwards and outwards, vent hoods always work better if they are at least 6" larger than the cooktop that they are covering below, If you move to a 36" cooktop, you would ideally have a 42" vent above it. And at least 27" deep. For your wall oven, if you want to replace it, your cabinet needs to be the right size to accept a modern oven size. That standard has become 30" ovens, which usually take at least a 31" cabinet in custom cabinets, and a 33" cabinet in standard dimensioned cabinets. It looks like a 24" oven in maybe a 25" cabinet? You also need to check the spot where the fridge is, and measure it. It too may not be a standard size to work with today's appliance sizes. A regular free standing refrigerator needs 36" of width and 70"-72" of height. I'm also not seeing any drawer stacks in the picture that you posted. Many older cabinets didn't see the usefulness of drawers, so all you got was a single one on top of doors rather than a whole stack of drawers. Are there any roll outs below, or is there just a half shelf? Site built continuous cabinets with no internal divisions? If everything works currently, other than taking down that shelf immediately above the cooktop, I think I would just live with it for as long as it took to accumulate the funding to address the rest of the 30 year old issues that the kitchen has, not just the appliances. One other approach that you may not have considered if you decide to keep the cabinets and just retrofit them is a 48" actual range where the cooktop is, with an actual hood above. That will give you two ovens. Where the oven is located now could be retrofitted by a good cabinet maker to accept a MW on a shelf so that one could get off of the counter. Maybe you could do something like a cutting board/baking sheet rack similar to a plate rack with the leftover space from the oven cabinet.

@sktn77a thanks, good idea. a lot of the house I moved into feels very...custom, so I assumed whoever installed the Jenn Air unit also did some janky stuff. the sheet metal duct feels pretty secure to the wall, but i'm reading that i might be able to shimmy it out once I've detached it from the downdraft motor. @jennsbabysky right now i have a microwave range hood combo with recirculating venting. I am confident the downdraft venting was compromised when we moved in (we didn't bother to look until years after we closed; big mistake - the downdraft motor hose was completely severed from the unit for what looks like a bit of time), so we weren't really venting anything efficiently (if at all) when we were cooking. for now, i am fine with recirculating, but maybe when a full kitchen remod is appropriate, we revisit proper venting.

"the cutout which is 30" w by 24" D. My only choice seems to be a range with a built-in downdraft flush with the cooktop." Need pictures. Is it a 30"-wide version of this? https://www.youtube.com/watch?v=0mhKFTiNZKM