I went in again today and picked out the smallest one they had that appeared to be the healthiest. This may be a very difficult process in finding one that is going to survive, though. I did speak to someone today and they told me that Thursdays are the day they typically get them in so I'm going to see if I can check back in on those days. In regards to the identification, I am leaning away from variabilis now. My reason is that I have yet to see any cirri above any of their eyes and the one identification paper I can find states that they have 5-8 cirri above each eye with one being more pronounced than the others.
For this second one, I decided that the tank was not helping as it was too small. I moved the tank to my workshop which hovers at around 50 degrees. This tank has built in filtration that I gutted long ago and now simply serves as a tank with a few empty built in chambers. I added a bag of carbon and phosphate remover along with a makeshift bubbler for carbon filtration made out of a Del Monte or Dole (can't remember which) plastic peaches jar and also drilled the back of this tank to install the ice probe. I figured that with a maxi-jet 1200 as the return pump I would be adding heat to the water and the ice probe could combat that heat addition and equal it out.
I still have 2 emerald crabs in there with the octopus, same ones that were with the other one. It has shown no interest in food, either, but it's only been in the tank for a few hours and had some adjustment to go through. One thing that is mildly encouraging, at least I think it is, is the fact that these guys (not sure if this is a male or female) seem to be producing strings of excrement, some of which have some actual black substance in them, some of which are clear. I am hoping that this means that it has had at least some nutrition recently and that it's not too emaciated to survive.
One other thing I noticed about these is that they have very "boxy" arms. They are squared off and the top of the arms, at least the ones I can make out clearly, are flattened and have square corners on all sides.
I wish that there was a store that had live ghost shrimp near me, although I'm not sure that they would survive being added to 50 degree water (right now it's at 58). I also may try a goldfish or a rosie, neither of which is a good option for the long term but if it can get it to start eating, then that'll be worth it. I am leaning towards a goldfish as I can temperature acclimate it without it dying and then release it into the tank to see if there's any sort of feeding response based on a fish swimming around. I may also try a live mussel or a clam, but I am not sure that this octopus has enough strength to open one and I'm not wanting to foul the water, despite the cold temperatures.