Not to rain on your parade, but Dolphin vocabulary according to the article is 200 words. That's a two-year old. Don't expect to talk philosophy with it anytime soon.
I also couldn't get information on whether dolphins combine their noises in a systematic way. Because language isn't just words, it's grammar - combining words to form sentences, sentences to form stories and conversations, etc.
And the octopus... did you look at the timeframe? Long-term recall was 24-hours later. I would hope that if I learned to distinguish a red ball from a white I would be able to do it the next day.
They're intelligent, very intelligent, but the gap between them and humans is still enormous.