Pronouns and possessive forms

How to make possessive forms of pronouns and regular nouns:

Pronouns we memorize, though you do see some patterns throughout:

• I = நான்; my=என்
• you = நீ ; your = உன்
• you (polite or plural) = நீங்கள், your= உங்கள்
• we (exclusive)= நாங்கள், our=எங்கள்
• we (inclusive)= நாம், our= நம்
• he/his அவன்/இவன்;  theirs = அவர்கள்/இவர்கள்
• she/her அவள்/இவள்;  theirs = அவர்கள்/இவர்கள்
• he/she/his/her அவர்/இவர்;  theirs = அவர்கள்/இவர்கள்
• it (close, here)= இது; its=இதன்; theirs (neuter)=இவைகளுடைய
• it (far, over there)=அது; its=அதன்; theirs (neuter)= அவைகளுடைய

Regular and proper nouns seem to have two options:
Add the suffix "oodaya" or "in"
above we see that "it" uses "ளுடைய"
other examples: house= வீடு; house's = வீடின்
I am currently in the polling stage to find what the rules are.
When do you use "in" and when "oodaya"???
Are they essentially synonymous?

Possessive/Genitive form is expected in chapter 5 of Hart's Tamil for Beginner's though it is introduced without much explanation, and the accompanying grammar book does not have a section for it...
In Asher's Colloquial Tamil "ooda" is used to designate the possessive form: "peeraasiriyar professor; peeraasiriyaroo∂a professor’s."