Higher levels of carbon in the ocean are causing oysters to grow slower, and their predators — such as blue crabs — to grow faster
Under conditions with lower levels of carbon, two mud crabs polished off 20 oysters in six hours. But in the aquariums with higher levels of carbon, the mud crabs seemed confused. They went over to the oysters, but they didn’t eat as many — sometimes fewer than half of what other crabs ate under normal conditions.
Voyager has no need for power to continue its journey; running out of power will have no effect on its velocity.
You're forgetting drag. Just like flying through air, flying through parts of the solar system results in drag from dust. The dust density is expected to increase when the probe reaches the inner Oort cloud, unless Voyager 1's path has angled enough above the ecliptic that it manages to miss it (I thought 35 degrees was high enough, my colleague disagrees.) If dust density increases, the drag will provide a small but continuous slowing effect. Once past the inner Oort cloud dust density will likely decrease, though no one I've worked with has a great guess of the dust density in the outer Oort cloud. It will still be non-zero though, and Voyager can't avoid the outer Oort. Added to the small but still present force of gravity from the sun (which is what keeps the Oort objects from drifting away), you have continuous drag on the craft.
We can't calculate the effect of that drag without knowing the dust density, and our estimates of the size of the Oort clouds are still rough (on the order of +-100AU last paper I read), which is why that NASA paper estimated crossing the outer edge of the Oort cloud in a range from 14K to 28K years. 14K if the Oort cloud is small and fairly dust-free, twice that long if our worst-case estimates of the density and size are correct.
the linked stories don't mention how big a change in radiation was experienced. Are we talking 10%, or a factor of 10?
Yes they did, from TFA:
"Anomalous cosmic rays, which are cosmic rays trapped in the outer heliosphere, all but vanished, dropping to less than 1 percent of previous amounts."
"galactic cosmic rays – cosmic radiation from outside of the solar system – spiked to levels not seen since Voyager's launch, with intensities as much as twice previous levels"
Its already pasted the ort cloud
No, according to NASA's Voyager project page, Voyager 1 won't escape the Oort cloud (really the outer Oort cloud) for another 14,000 - 28,000 years. (Probably due to running out of power in the next 10 to 15 years.)