1. Which law are you referring to seeking clarity on 'resident'
The law pertaining to flats or apartments differ from one state to another hence you cannot base or infer any meaning based on the general law to this situation.
2. A owner member of the association can contest if he has taken possession of his flat
3. If they have not let out their flats on rent, it can be deemed that they are in possession and occupancy of the flats.
4. Yes, why should they not, give me one good reason that why they are not entitled?
They are the owner and member of the association, they have not let out their flat on rent, they are holding the keys of their flats and they are paying maintenance like other members, so what is your objection to it?
The election rules can give only guidelines and it cannot clarify your imaginary doubts or it cannot go deep into specific doubts that may arise out of one's imagination.
You can accept the rules as general guidelines and proceed, as a election officer,m if you feel that certain aspect is not within the ambit of the rules framed for the purpose, you can refuse to accept the same, let the aggrieved knock the doors of the court with their own interpretation about the prevailing law and seek remedy.