Yes it is possible to mount an accu-trigger to a Stevens 200 action, You would have to cut the spring and turn the screws out a bit, the spring will sit cocked, Is it safe I say NO.
The Savage action gets extra maching steps for the accu-trigger, that the stevens does not, To do it right the stavens action would need this extra maching. Also the Safety and trigger mounting bracket are diferent between the two rifles.
To further add the new 6oz accu-trigger has a diferent sear than that of the acc-trigger rifles, the sear can be ID from a demple in the side of the tigger release lever. So to use the new target accu-trigger in a accu-trigger gun the sear would need changed out as well. The sear has a diferent angle on it, that is how they removed some of the weight of the trigger. Again I would not place this trigger or any accu-trigger in a stevens gun.
As the others have mentioned the SSS trigger is a far better trigger than the accu-triger, and is a drop in for your gun. Also the Rifle basix sav 2 trigger is good. The SSS trigger will go to 12 oz where the Rifle basix trigger will go to 4 oz. The SSS trigger is cheaper, and many say it feels better than the others.
I would not buy a Rifle basix sav 1 trigger or a timney trigger, yes they are a direct drop in, but they do not differ much from the old Savage factory production 3 screw trigger, that can be had for about 20 bucks. The sav1 and timney triggers are about the same price as the SSS trigger.
All I can say is once you have tried a SSS trigger you never want to touch another accu-trigger.