Ilosean Shayana, AKA this is your English on space drugs.

[mèþru]

Mèþru, I doubt that the allophony shift can make sense if it occurs before the vowel deletion - I can see the yod-insertion arising spontaneously, but nothing else.

It occurs between the first and second elisions, of which the latter is the same as your current elision except sound changes I've introduced before it have made it affect more vowels.

[Knit Tie]

And here we go! Ilosean Shayana V 3.0, and I'm thinking of naming one of the famous in-universe poets Mètru (or, if you wish, Mèsru) in honour of your contribution to my conlang - perhaps he will be one of the pioneers of literature written in the colloquial speech of his time, as opposed to the older form of language that will have been dominating the writing until his advent?

Although I must ask you a question regarding your terminology, what exactly did you mean by

To compensate, /e̞ ɛ̃/ become short when between stressed syllables

and by

In addition, /i ĩ/ lower to /ɪ̆ ɪ̃̆/ when between stressed syllables

? I wrote these sound changes as occuring before stressed syllables in the document.

[mèþru]

I didn't read over it close enough. I forget exactly what I meant, but I think it was shortening both between two long vowels and between a stressed short vowel and a long vowel.

[mèþru]

I'm thinking of naming one of the famous in-universe poets Mètru (or, if you wish, Mèsru) in honour of your contribution to my conlang - perhaps he will be one of the pioneers of literature written in the colloquial speech of his time, as opposed to the older form of language that will have been dominating the writing until his advent?

I am deeply honoured. mèþru is pronounced as /ˈmɛθ̟.ru/ (I try to be exact with IPA, like I will not use /r/ to represent a phonemic non-trill. This is a phonemic, not phonetic, representation, but I think that it won't be that different when I finish the allophony of agefaqeg). If you give a specific period after I finish with Shayana 3.0, I can try to find the best phonetic representation of the time period. It might be tough on your end to find a good etymology explaining it.

[Knit Tie]

Seeing how Shayana borrowed heavily from other languages (via assimilation of other peoples into the Liin society), I'd say that we need not bother with any etymology at all - we just say that it's a loanword. As for the phonetics, it's probably going to be pronounced as [mʲɛɐdɾ] (standard dialect), [mʲe:ʈ] (local Cockney analogue and related dialects), [mʲɛɐtɾ̥] (the Phoenicians) and [mʲi:dɾ] (the nomads) by the time the story takes place in-universe.