HCA: Hermit Crab Association

My new 75 gallon tank is almost set up and ready to move the critters into, but I've had one of my crabs down for litterally 2 to 3 months now. I can move the others, but should I risk digging down to see what's up with Arlie? I have a general idea where he is, but I'm really not sure if he's still alive and just being antisocial, or if he is no longer with us.

What should I do? After I get the others moved over, I really need to clean out the current tank and get it out of the way soon. I know I'm not supposed to 'go digging', but what else can I do?

Any advice would be greatly appreciated!
Thanks!

I would leave those buried be in the old tank until they surface. As they surface, move them over. If you must absolutely only have the new tank going (I understand those reasons as I've been there), then have a few ISOs ready for molters uncovered, such as your guy who's been buried a few months.