What is your end goal?
Can you live with four GV accounts and two physical telephone lines? If so, use the 202 and retire the other OBis. If you can't, then use the 202 and one or both of the others.
Why do you need four different GV numbers?
RE: 911, if you get rid of the 110, then either keep a phone plugged into the POTS line, or use your cell phone. Personally, I wouldn't rely on a decommissioned POTS line. You won't know if it somehow got accidentally disconnected until you pick up the phone and it's dead. If you DO use it, it won't provide your location, because it won't have a telephone number, unless your telco has worked out some sort of substitute procedure.