It would have to be a redesign, but not much of one.
I am slightly wondering about the chip dimensions. You have stated that ActiveMining chip package dimensions are going to be 11mmx11mm. However I believe bitfury chip package dimensions are 7mmx7mm. The board seems fairly tightly packed with the 7x7mm chips. If you increase the size of package you would have to decrease the number of rows and columns of chips to make them fit. So I do not understand how this could be not much of a redesign as basically everything changes.
Changing the chip dimensions and even moving them around really isn't much of a change. It's a pretty simple respin of the board that wouldn't take more than a couple days, maybe one if you sat down and worked on it full time. As long as the interface and communications protocol is similar, the size of the chips is pretty much a non-factor.