The suckers definitely do not suck
I don’t think you need to overanalyze the suckers placement. The last picture shows a good varied placement and size. I would rather you added a few pronounced wrinkles around the eye region. I know it is slightly out of character for a sea creature but your final render might see the suckers steal the limelight. A couple of deep set skin indentations and a decent set of eyes should keep the extreme detail of the suckers from grabbing all the attention.
Anyway I am just a sucker with an opinion Damn, I am losing it
Love your progress so far. Impatiently waiting for a textured render.