(non)questionable pronouns

[Blue Elf]

Kaltxì ma eylan,
I'd like to ask some questions about pronouns, for which I didn't found good answers:
- are there nonquestionable pronouns who, where etc.? Standard tupe/pesu, peseng/tsenge etc. can be used in the questions only, but how to say: "Who comes the last, won't get the dinner" or "Where is the lightning, there is also thunder" ?
- how to create question for "which in the sequence", like "Which day in the week is Wednesday? (The third one)" (or the fourth, depends on region). We have trrpeve for "which day", so is there something like holpxaypeve?

[Plumps]

I believe the answer is the same as in English and other languages

tute a za'u hawngkrr ke munge wutsot
cf.: he who comes late won't get dinner

Same for the second ... although I'm not sure how to create that correctly
tsenge a tok kxenerìl kop txepìl tsatsengit (I shifted semantics a bit since we are waiting on the rest of the weather terms )

Concerning the second, I'm not sure. It could be a simple trrpe/pesrr solution

[omängum fra'uti]

The word for "non-questionable pronouns" is relative pronouns, and you are correct that the pe+ forms of words can not be used there.  You can generally just use the root form of the word, and attribute a clause to it.

Tutel a za'u nìsyen kea syuvet ke tel.
Who comes last won't get dinner.

Oel ke omum 'ut a pol tsat nolew.
I don't know what he wanted.

I'm not sure we have a word yet for your second question, though depending on the context you could potentially word it differently.

[Blue Elf]

Irayo si, ma meylan. I thought the similar way, but was not sure.

[Blue Elf]

Well, as we have example of using pe- word as relative pronouns from karyu Pawl:

Pol pole'un futa pehem si nì'en.
He decided what to do on a hunch. (source: http://naviteri.org/2011/01/new-year-new-vocabulary/, comments)

it is time to ask again: it is allowed and safe to use pe- words not only in questions? Was there any discussion about this?

[Sireayä mokri]

it is time to ask again: it is allowed and safe to use pe- words not only in questions? Was there any discussion about this?

There was another example: Furia fyape fkol serar lì'fyati awngeyä, leiu set nìlaw pxaya sute a oeto lu sìltsan! So I assume it is indeed allowed.