Overall a cool idea -- I like the idea of the bioluminescent energy being what fuels their society but also attracts the humans, and I agree that having the humans be the antagonists is a neat perspective shift.
There are a lot of components to the described game, that make me feel like scope will be an issue in terms of getting all of this done in the time available. Particularly each one of the abilities the octopus have are really enough for a single game in this unit due to their complexity, and so having 5 of them may be time consuming. In addition it sounds like a lot of different levels each with different graphics are planned, and on top of all of this there appears to be a social system (alliance building), resource management, and stealth. Again each of those systems is enough to comprise a whole game for this unit if done well.
I encourage you to prioritise what is needed for a "Vertical slice" that shows off the core idea of the game, and what will net the most marks for assignment 3 (read the rubric). Things that feel easy to cut are the stealth aspect (difficult to balance, and not needed if there is already standard combat), alliance building, camouflage (unclear how you will implement this without shaders), object manipulation (this might feel under-cooked if there aren't enough items and variation to this). However you might have a different prioritisation/opinion and thats fine.
Finally the tentacle control sounds complicated given that there are only two sticks available to a player, and I can't quite visualize how the other tentacles would be controlled by just a trigger or button alone. This may need to be simplified to avoid being confusing or frustrating for the player -- you should definitely prototype this first to see if the player movement you have in mind is actually fun/feasible.