Llananno Girl?

I think my favourite Radnorian poem is Lewis Glyn Cothi's 15C request for a bed, made to four local good women. Here's a short extract followed by my attempted at a translation:

Y nos y câr fy nisyn,
Fwrw ei led ar gylched gwyn,
Cysgu awr, o cwsg erof
Estynnu uwch sidan of.
Tew o led, motlai ydyw,
Tyner rhag y tanrhew yw.
Lle meddal mal y plu man
Lle esmyth oll i hwsman.
Dis ysgwâr o gadas gwyn
Dôr uchel rhwng dau erchwyn,
Erw o ddillad werdd wellwell,
Allor gwsg yn llawr y gell.

My little dice loves the night, he throws himself on the white coverlet, to sleep an hour, stretched out on pure silk, away from me. It is thick and many coloured, tender against the scorching frost, a soft place of small feathers, a place of rest for a labourer. Square dice of white braid, a high door between two bed walls, an acre of superior green bedding, an altar of sleep on the cell floor.

Of course what the bard is really describing is the grave, in a poem which recalls, by the use of the words fy nisyn - my little dice, the well known elergy to his small son Siôn y Glyn:

Fy nwy ais, farw fy nisyn,
Y sy'n glaf am Siôn y Glyn.
Udo fyth yr ydwyf i
Am benaig mabinogi.

My ribs ache for Siôn y Glyn, my little dice is dead. I'll weep for evermore for a chieftain of childhood games.

So who were the four goodwomen? The editor of the 1995 edition of the bard's work identifies them as Gwenllian, the daughter of Owain Glyndwr who lived at Cenarth, St Harmon; Efa vz Llywelyn of Rhayader and Elen, a daughter of one Gruffudd Goch. His fourth identification Mallt, the daughter of Ieuan Fychan of the descent group of Rhys ap Tewdwr doesn't seem right at all to me. That Mallt came from Bryn Coch in Llansantffraid-yn-Elfael whereas the Mallt of this poem is described as:

Mallt ferch Ieuan Fychan fydd
Moliannus ym Maelienydd;
Elystan yn Llananno,
Hon yw y ferch o'i hyn fo.

Mallt the daughter of Ieuan Fychan will be praised in Maelienydd; this girl in Llananno is formed from the being of Elystan.

Now I don't know how accurate my translation is, but it seems to me that the bard is saying that she comes from Llananno and is descended from Elystan Glodrydd. A candidate might be an unnamed daughter of Ieuan Fychan of the small local descent group of Y Dean Du, her mother would have been from one of the many families claiming descent from Elystan.