Well, since your symptoms and causes seem to be fairly different from mine, i don't know how much i can offer you in particular.
If you can afford it, a one handed keyboard is the first thing i can think of off the bat. enablemart has a one-or-two handed (it can be used as both) keyboard for a fairly reasonable 150$. They also sell extended zipper tabs as well as button-closing aids.
An electric can opener can be had at almost any store that sells small kitchen appliances, as can grips for jars. Door knob grips like
Maddak, Inc. * Aids for Daily Living can be purchased (as I did) or scrapped together with stray rubber. Adding a grip to your key might be unattractive, but it will both make finding your keys easier (if you keep half as messy a purse as I do) as well as executing the task of getting the key in the door and twisting it. Likewise, lamp grips (from enablemart and many home health stores) are the difference betwen a pencil sized gripping surface and a can-of-peas sized gripping surface.
one thing i cannot stress enough is adding a pan holder to your stovetop, which can save you from major accidental burns. This will stop the pan from turning around if you stir one-handedly and provides some protection from the pan falling off the stove, unless you pull it straight back so that it's out of the holder- any side-to-side motion wont dislodge it.
using a suction-based scoop bowl is helpful in both preventing you from moving around the bowl with your spoon or fork and will also provide a surface to easily lift food into whatever you're eating with. Since they're plastic, they'll survive falls.
wide gripped spoons and forks are great, but very expensive. Using a snap-on modifier meant for any spoon or fork may help, but in the end it's up to you if that's worth it.
Regarding lidded cups, the best invention on earth is a sports bottle with the mostly one-way valve, so when you suck on it it'll open up and pull back in air, but once you're done, you don't have to snap the bottle back shut- you can tip it over or send it flying and it wont spill. It beats fiddling around with capped sports bottles!
those are just the handful of suggestions i can offer looking at- i'm sure you can find yourself plenty more in regards to whatever you have difficulty with, especially working with your therapist.