Can "catnik" refer to men also? The sentence works with "he" instead of "she", but doesn't work for "handsome" instead of "beautiful", so is it just Duolingo mistake to accept the "he" translation or is the word correct for both genders?
No. In Indonesia, "Cantik" ONLY refer to woman, and and for men we usually use "Ganteng" or "Tampan" which means handsome. So, I think it's Duolingo mistake here
For women and cats, as Doulingo shows us. Thank You very much for the answer!
Why wouldn't "she was..." be accepted here?
'Dia tinggi dan cantik' can also be used for past tense, but I prefer using 'Dia dulu tinggi dan cantik' or 'Dia dulunya tinggi dan cantik' which means 'She was once tall and beautiful'