steady aspen
so i have all 41 ocean things done, ive got both mines finished, ive got an upgraded museum, ive got 5+ hearts with like 6 townspeople, and most of the others have 1-2 hearts, and im at the end of spring 2, but im still stuck on my town rank 
ill never unlock animals and the bundle crops at this rate ugh.
and yes, im positive i have all of the beacons done, ive checked twice using the underwater map 
shadow nebula
it looks like you're close to rank C, you might have to donate some more bugs/fish/gems maybe?
opaque zodiac
How many sesajen/offerings have you done? But yes, I think it's the Museum too, upgraded is not enough (I think that's around 50?), for the rank you need it to be around 100 (113 for me)
south star
if you already done all the the beacons and 5 offerings, you need to donate more items to the museum, I reach rank C around 114 items iirc
opaque zodiac
(it also works without having 5 offerings, mine unlocked with only 4 completed sesajen - but I think you need to have done more of the other stuff then)
steady aspen
I’m only missing the three (fall) items from the winter bundle with the first alter. I’ve completed all the rest. And I can’t complete the last one without being rank C 😦
Idk how to check my total number of donations but I know surely I’ve donated over 100. I clearly have 50 because my museum is updated but I’m almost positive I’d have 100+
opaque zodiac
I've heard of people needing up to... 125 donations I think? So maybe you're close and only need a few more!
You can only check the number by counting the green Museum Icons in your journal right now unfortunately
nimble canopy
Also, make sure to buy fossils from the night market lady and donate those
spiral echo
It is also impossible to 'unlock' any animals at the moment. The only farm animals in the game right now are cows and chickens.
pseudo thistle
Also, make sure to buy fossils from the night market lady and donate those
This is what got me to rank C so i can confirm that this works wonders for that last boost!!!
steady aspen
Also, make sure to buy fossils from the night market lady and donate those
ive checked a few different times and her boat never shows up. i see her in the tavern on the days shes supposed to be in town, but her boat just doesnt show up 😦
ok post update, i have this. but again how do i have a D rank for ocean when i have all 41 things unlock 😦 i even double checked before sending this post lmao. im losing my mind
like it even says 100/100 for the next rank lmao