No, you don't need to soak fresh shell beans.
Unlike their dried counterparts, shelling beans don't need a soak before using. Most fresh shelling beans require from 20 to 30 minutes to cook
The Spruce Eats
I'm not sure where they got the idea that most fresh shell beans take 20-30 minutes. You'll find recipes that vary from 10 to 60 minutes of cooking ...
It worked phenomenally!
I quick-released my stew ~5 minutes earlier than usual, added the frozen beans (no extra water needed- the beans were just covered by the liquid) pressure cooked on high for 7 minutes then allowed to release naturally.
The beans were buttery but totally intact. Would recommend.
I see instructions for pressure cooked frozen butter beans, which call for 4 minutes at high pressure, followed by about 10 minutes of natural pressure release. So, I would certainly add them at the end. Fresh beans (or frozen) don't absorb a lot of liquid, and you can certainly add more liquid to thin afterward.