Second person plural pronouns are the same as second person singular, as shown by dialogue from Alduin: Meyye! (...) Zu'u hin daan! "fools, I am your doom".

Thus subject/object/possessive = hi/hi/hin. The reflexive is not attested, but can be derived from a regular pattern: himaar.

'Their' is entirely unknown. I recommend substituting do niin, lit. 'of them'.