I can give a local perspective since I was in a congregation at the time (2010-2011) when these donations were accepted.
The plan was presented at the time to put up for sale the Indianapolis Indiana assembly hall and the London Ohio assembly hall, use the money and collect more donations to build a more centrally located, new-design Assembly hall in SW Ohio (near Cincinnati). The new hall would seat about 3500, and would be used for both circuit assemblies and a slimmed-down district/regional convention series in the summers.
The need for donations was supposed to be $8 million over and above proceeds from the sales of the two halls. Our hall took a survey of 'pledges' and came up with the figure of $600 a month to donate for the SW Assembly hall building fund. There was a special contribution box at the back of the hall just for it. The WT proceeded far enough to buy the property, but I don't think there was any movement beyond that. There was significant opposition from the local authorities over allowing a non-profit to use the chosen properties (it all had to do with the lack of tax revenues, and the area they had selected was in an industrial park).
The Indianapolis Hall sold a few years ago; I don't know where they are having their assemblies. The JWs are still using the London OH building as they always have,as it never found a buyer and was taken off the market. .
The 'special box' at the back of the hall disappeared a couple of years ago (about the time the KH mortgages were 'forgiven') and no mention was made of the status of the collected monies which had been forward to WT specifically for the SW Assembly Hall fund.
Now, on the Indiana side, apparently as the OP states, they are going to take the money for the WW work after resolutions pass (the initial donations took a resolution as well, if I remember correctly). I can't confirm that on the Ohio side they are doing the same as Indiana, though I expect they are.