You’ve left it a bit late for a comprehensive answer to a very comp0licated question. There are all sorts of things to consider such as how many votes does the developer currently have (if he still owns more than 50 percent of the properties his voting power is reduced to one-third).
I reckon your EC needs need to pay for a strata lawyer to sit in on the meeting and advise of the legalities, preferably at the developers expense (but not their choice of lawyer).