Whether flat owners can put injunction on my under construction residential building

Builder sold me falt +parking. flat through registered sale deed and parking through stamp paper. later on i found that he sold same parking to 2 flat owners. other residents in society has parking in registry document but builder gave me parking in stamp paper separate from registry. later on raising dispute builder offered me parking in open space but now society said its common place and cant be sold by builder. Further i found that builder has not followed development authority parking norms as well.

Property was allotted to father and it was registered to child 1(A).Later A gave SPA to father to register the property on Mother. Also gave gift deed to be on mother and child 2 or sibling of A.Father executes SPA and property got registered on mother and child 2. Is registration to child 2 valid since SPA was to register to only mother. Can mother and father build a house in the full property. Will they need a partition deed to avoid future issues with child 2? Please advise.

Is it a case of 420 if a person sells the property under his name but belongs to other person in mother’will.