mi moku e seme?

[loteni]

mi moku e seme ?

pipi li pali e seme : ona li jelo. ona li ko. ona li suwi.
pipi li seme : ona li jo e linja jelo e linja pimeja. ona li jo e palisa jaki tawa utala. ona li tawa lon kon sama waso.

pipi li pali e ona. mi pali e telo nasa kepeken ona. mi moku e ni.

mi moku e seme ?

[janKipo]

The first 'ona' is strictly illegitimate, since there is not prior noun for them to replace (except 'pipi', which clearly does not work). Maybe 'ko li jelo' and then 'ona', or some neutral word like 'ijo'.
The pipi isn't a yellow stripe or yellow hair, it has them. tp doesn't have collapsed exocentric modification apparently (I thought I saw a place for it, but it didn't work out).
The answer is probably something like 'ko jelo suwi' as you said.

[loteni]

Ah thanks, I had too much of the answer and missed the jo

the first ona is replacing the seme, which is a something that operates as a question to replace with required object, which can be a noun compound.

pipi seme li ona, kind of looks weird, but pipi li seme i should use i think... ill edit that...hmm now the whole structure looks wrong...

[janKipo]

or you can just go straight through as in English
pipi seme li jo e linja jelo e linja pimeja e palisa jaki (pi) tawa utala li tawa lon kon sama waso (it doesn't really, but that is all technical stuff).
but you are right that 'seme' does provide a referent for 'ona'.

[loteni]

shame you cant do a ... tawa waso lon kon or something...?

[janKipo]

But of course you can -- and be understood, too, as well as grammatically correct.