I have managed a couple of smaller office moves in the past. One year is not a long time unless they already have a property in mind and ready to sign a P&S. Generally with commercial properties, there has to be significant modifications to the buildings they are going to buy (or lease if they want to free up some short term cash at the expense of future lease payments). The commercial market is quite busy inside the 495 corridor. Architects have to get involved, buy in from the client including the staff has to be obtained and then contractors need to do their stuff. The alternative of just moving everything to a raw space and doing the upgrades after the fact while the space is staffed is more expensive and quite disruptive. Assuming they have at least one large public space (theatre/auditorium) a library/archives and private offices for management this could be a 6 to 9 month effort assuming they have the cash in hand. If fundraising is needed that adds in more time. I would expect that rather than fund raise they would raid a reserve or take a short term loan.
I am assuming a vacant spec type commercial building, if its a vacant historical property being adapted to a new use, add 30 to 50% minimum to the timeline. It will be interesting to see if they insist on a location on the actual subway system or if they are willing to go with a location served by commuter rail. The little I know of the T system is that access to the core of the system is lot easier than an outlying train station. Individuals living on the "wrong" side of town may be resistant to voluntarily adding a substantial increase in time to their commute. Of course they could go the GE route and just ignore the staff and put it where the board of directors wants it to be and use the move to shake out staff.