I ended up running a quick test, lol. I tried out the Still background feature, but when I hit the New still background button, the text doesn't translate, and this happens with both manga and games. It successfully updates the background image, but it keeps showing the translation from the previous image instead of the new one.
I do want to point out a positive side effect: the Still background feature actually eliminated the text displacement problem I was having in Stream friendly mode. At least when the feature is active, the text displays correctly. It's just a pity that the new text doesn't get translated.
Obviously, this doesn't fully solve my Stream friendly mode issue since it only works with the Still background function for manga or vn, but I definitely see this as progress in the right direction :)