A Star Trek script writer, comes to you and says: I want you to
translate in klingon, the phrase "kahless, my light".

Suppose that the "my light" is used metaphorically; would you use
{qeylIS, tamghaywIj} or {qeylIS, tamghaywI'} ?

And suppose it's used literally; someone sees kahless being made of
light (he's a god after all..). Would you use {qeylIS, tamghaywIj} or
{qeylIS, tamghaywI'} ?

And of course, the script writer says, that you *have* to use these
two words in apposition; i.e. no recasting, no rephrasing,

I would ask the scriptwriter if they really want my help after all.  They seem to have decided on my translation for me.

Metaphorically, I'd probably use tamghaywIj. Literally, I'd only use tamghaywI' if we were actually talking about a being capable of using language that I wanted to refer to as a light. I think I'd be very unlikely to do so.

Klingons do not have rigid lines of demarcation when it comes to deciding whether a noun counts as a being capable of using language.

The plural suffix for birds is usually -mey, the general plural suffix, as would be expected. There is a difference of opinion, however, about which plural suffix to use for a few birds capable of mimicking speech, such as the vIlInHoD and the qaryoq (and the larger qaryoq'a'), with some Klingons using -mey but others preferring -pu', the plural suffix for beings capable of using language. Maltz is a member of the former camp; he said he was never able to engage a qaryoq in a conversation that made any sense.

HolQeD volume 10 number 4

You're basically picking at an issue you don't really need to. Take your best guess, and if the noun really doesn't obviously fall into one of the genders, nobody'll blame you for your choice. This is an area where "good enough" is all there is.

-- 
SuStel
http://trimboli.name