Lacus and her father were branded traitors for going against Patrick Zala, so it would seem that everyone else who disagreed with him would join them, which seems to be a lot of people that I am sure include people from all levels of the ZAFT military. As for the mobile suits I am sure it is possible that they have done some spying on ZAFT for technology, and ORB could provide them with resources to produce mobile suits since ORB seems to have no trouble building itself an army it could possibly have extra resources for Lacus to use as well. I don't think the factory is as big a stretch as you think it is, although I admit that it is a little obsurd to have set up a factory floating in space just in case you can no longer go anywhere on Earth or in Space.