As far as I know, community made words aren't used on this site anymore. As for possessive forms of They and it, Nustiil, Nust "They" with the possessive suffix -ill "Your", no idea if that combination works or not but its there. Or the words "Nust piraak" "They have" could work. For it/it's the word Nii "it" already contains a possessive suffix for "His/Her's/it's" which is -ii. But you could also say Niiro, Nii "it" with the possessive suffix -ro, which means " 's " Also unsure if that works or not.