ní ba ... ná ... = more ... than ...

Is mó cuma agus crot (= cruth) a chuir sí di an oíche sin = Many a form and shape she gave her that night
agus bhí gach cuma díobh = and every form of them was
ní ba ghránna is ní ba mhallaithe ná a chéile = uglier and more cursed than another (= than the other)

BTW: ’ná = apostrophe in old spelling because of ioná, the Classical Irish full form.

Go raibh maith agat.

What does this mean ? - Fúinn na smól - Under us the embers ? or is there an idiomatic meaning to it ?

You really must put it in context and give us more than those three words. In the CO an smól = nom. sing.; na smóil = nom. pl; na smól = gen. pl. So, in CO terms anyway, it can't mean what you say (but may do if na smól is an unlikely dialectal variant of the nom. plural). Are you sure you've copied it correctly (you do have previous after all )?

It's the name of a book of songs collected by Father Patrick Walsh - one of them is included in the book Sliabh na mBan bhFionn written down by Father Peter O'Leary from his recollections of the story. I've managed to get an original copy of it, as some of the chapters are missing on the forum.
What surprises me is that the fada is on the i - ie Fuínn and not on the u. I've ordered a copy of it from John's Bookshop.

I wonder if it is related to this word:

http://www.teanglann.ie/en/fgb/fuin


If so it would mean cooked over embers.

There you go again . In your original post you had fúinn, now you say it's fuínn ( I did ask if you had copied it correctly).

Check it again. Is it a fada or just a dot over the 'i'?. Could it possibly be foinn - nominative plural of fonn = air, tune, melody, song? And fuínn (if indeed that's how it's spelled) is possibly old spelling version, dialectal version, franc91's eyesight version?

Foinn na Smól - literally, 'Airs of the embers/Ember Airs'?

I wasn't at all sure about it - it could have been a mistake for all I know. I automatically thought it was fúinn. In one list, the book is 'Finn....' but as I haven't received it yet I can't say exactly what's on the cover. Very often in the text in these books, the printing isn't very clear - the r, s and m can be quite difficult to make out, but of course these are the original copies, so they're quite old. The other one I'm reading now is 'Rí na mBréag' which I've downloaded from Internet Archive and it's not always easy to pick out the individual letters.

There's online a scanned copy of the preface by Pádraig Breathnach and a few letters by Peadar Ó Laoghaire to P. Breathnach about the songs, both in English (here: https://corkirish.files.wordpress.com/2 ... mc3b3l.pdf)
But without any explanation of the title.

It is written Fuínn na Smól there.

It is written here so as well: http://www.ainm.ie/Tag.aspx?Type=opus&S ... &Valyoo=Fuínn%20na%20smól.

My proposal:
"tunes of the thrushes"

(smól: a variant of smólach, so in Standard Irish perhaps: Foinn na Smólach)

Go raibh maith agat