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I agree mostly with what BottleFed70 said.

I have run into 2 types insulation in freezers. Fiberglass in them is good perhaps for an oven, the solid foam is not.

As said you won't want to lean over the oven much to load/unload it. Stand it on end upright, or perhaps lay it on it's side so the door folds down towards you. Leaning over the open door may also not be fun, but you could probably cut the door in half and hinge the 2 ends so you have 2 swing open doors on the front.

Of course you need to remove any plastic or rubber parts, the inner lid is normally plastic and the magnetic seal rubber. Good pictures but I can't tell if the inner lid is metal or plastic from here. Also the Gray top of the chest, seal area, is often plastic so may need replaced also. If you can get that off and look between the inner and outer chest panels and it has loose fiberglass insulation you might be able to use it as is. If more insulation is needed perhaps wrap the outside of the freezer as needed.
I am not sure about the temps of fiberglass insulation. I know I have used a pressed board type that was rated something over 500F, it was used allot for outdoor wood burner shells.

If you can find a free or cheap junk electric stove that's where I would start first on this. Since your not sure on the electrics it might be a good practice and test of the freezer/oven. You could always buy other parts later and change things as you want.

First check that the oven in a junk stove does work! Unplug it! Take back off stove and trace the wires BACK from the elements to controls to see how everything is wired up. Most stoves are fairly simple. Try to get an old one with coils for the top burners, you can use those also.
Mark all connections as you take wires apart so you easily know how to wire them back the same way. Be careful with that thin copper tube with the fat bulb on the end, that is the thermo couple to read the oven temps and turn it on and off by temps as needed.

Once you remove all the needed parts from the kitchen stove just put them in the freezer and connect them same as they were. How you do this is up to you but that's basically it.
Put the oven controls in a safe box outside the oven (safe as in no shorts, and no shocks! )
Run the thermocouple into the oven and perhaps mount in center of back wall, some people may prefer mounting near the top instead, I prefer center as that would be closet to most parts I would be baking.
The oven elements should have had some type of holder to keep them in place, drill the needed holes and use same holders.

A working electric stove should have all the parts you need even the wire though you may need extra wire for a longer run. Really just a matter of moving them from one box to another. Doing this should give you a working oven and a very good idea how to wire one up.
If you wanted to get a bit fancy, you could even mount the stove top coil burners in the oven, use the controls for those to help fine tune temps for a faster heat up time and less temp swings. The press button controls on stoves are not nearly as good as the dial type.
With the dial type controls you can adjust from a low heat to steady red hot. If you took the time and effort you could probably dial in the 4 coil burners for a steady heat like 350F-400F then put those on a switch to just turn on/off when you want them.
So if the coils were set to 360F and just always left on, then the oven should hold a steady 360F. 360F is the lowest bake temp powder I have used so far. The oven elements and control could take care of anything above the preset 360F then as needed. Heatup time from cold to 360F would be faster when using the extra coils than with just the oven elements also. But setting those up might be more confusing to begin with, the oven parts should be easy to figure out.
This would be how I would start out and also learn about the wiring and controls, with a prebuilt unit and just move it to a new case.

Also the first time I heated up the freezer I would do it outdoors and heat it higher than I would for normal use. So if 450F was as hot as I planned to normally bake I would run it at 500 or higher for a few hours. This way if anything is going to burn off with heat like oils, old glues, paints, sealers, ect... it's not going to hurt anything and any fumes not in the shop area.