Extremely low FG

So i made a DIPA, on the brew day from hell. Im pretty sure it mashed around 140. Through a 2.5 hour boil and a huge preboil volume i somehow hit my target SG of 1.08. I pitched about 1.25L of started 3rd generation of WLP001.

Its been happily fermenting for 2 weeks. I thought it was strange that there was no blowoff, just a smooth fermentation, i assumed this was because its around 55-65F in my apartment.

I decided to check the FG today because this was the longest fermentation ive seen. It was very cloudy, possibly with yeast, and still had a small but strong krausen going. The FG is around 1.000-1.003. Immediately i just put the batch in the refrigerator as its still bubbling.

Will this make the yeast go to sleep and leave my FG relatively where it is?
If i want to dry hop should i remove it from the yeast before returning it to room temp?

Combine a way too low mash temp with a good pitch of 001 and I'm not surprised you tore through all the sugars. You might consider adding some maltodextrin to bolster the body. Cooling will cause the yeast to go into hybernation but not kill them so it won't result in stability. But, I couldn't imagine at your SG there is much anything else for them to chew on, you are most likely seeing residual CO2 come out of solution causing the airlock to be still active.

At this point I would rack the beer to dry hop since you are already clearing the beer from the yeast so may as well not undo that process by heating it back up.

Agreed.

A big fruity dryhop with a combo like Citra & Amarillo will help to create an added sense of juicy sweetness which might be necessary here.

Your mash was a little low. All the sugars you converted were fermentable. If you mash a little higher you will get a higher fg, because some of the sugars you convert out of starch won't be fermentable by the yeast.. Right now you will have a pretty dry beer, which will still be tasty for an IPA. A higher fg gives you a sweeter beer. An alternative would be to add a half pound or so of carapils to your mash. It converts into non fermentable sugars and adds body to your finished beer. I would test your hydrometer in some 65 degree RO water and see what it says as well. That is a pretty low FG for such a big beer at those low temps.

I also used 1lb corn sugar. All of these spells HIGHLY fermentable wort. While we're here could the extra low mash temp also affect conversion? like if i actually hit 148