I know oren is orange. However I think they could have chosen a more realistic eye colour?
I think the answer is that historically Welsh had no word for 'brown', Soil was described as being 'oren', so old Welsh texts may say someone had 'oren' eyes, meaning what we call 'brown'.
Traditionally llwyd covers shades of nondescript brown - papur llwyd 'brown paper', for example. gwinau is the reddish-brown of nuts and bay horses. eurgoch, dugoch, ...
Too many words for brown!
Yes, I imagine 'oren' didn't use to exist either! interesting to know that there are lots of words for these colours.
It shouldn't be. '... bright orange' would be fine, though - golau can be used in that way as well. But oren is definitely 'orange'.
I knew someone once who had the most lovely, strinkingly amber eyes - I saw them first in the sunlight and it was a very striking effect.
Perhaps not quite the same as orange but it is a possible eye colour.
https://en.wikipedia.org/wiki/Eye_color#Amber , https://en.wikipedia.org/wiki/Iris_%28anatomy%29#Amber_Eyes (which calls this colour "extremely rare" in humans).
I think it's a tiger or something. It doesn't have to be a person, necessarily.