Change in Sanction plan by builder

1)Builder announced a project in 2007 with 550. 2)Builder started giving possession in 2013 and finally transfer the to society in 2015. 3)Between 2013 and final transfer to society builder added 12 flats in Ground floor which were earlier common room for residents. 4)First MC gave share certificates to few these flats owners. Remaining owners are asking for share certificates on basis of this and approached registrar. Now registrar has order Society to issue shares as they have been paying maintenance charges. Q1)Prior to RERA, what was the process to change sanction plan? Did it require approval from existing buyers ? Q2)Can builder change a plan post possession and prior to transfer to society ? Q3)Due to change in shareholding changes, it would impact the ownership of individual owners. What are the rights of individual owners ? Q4)What are the options as MC seems to be weak and hand in gloves with builder to give benefit to these new flat owners based on ARCS order. Q5) Even for AGM these new flat owners are allowed to vote without assigned share certificates. Is that legal?