Under fáltas in Cnósach Focal ó Bhaile Bhúirne, this words is defined as follows:

But shouldn't it be beagán is ea fáltas? Does the order of words matter?

I'd guess this meant:

fáltas, 'sea beagán = "faltás, it's a small portion"

i.e. when spoken:

fáltas <pause> 'sea beagán.

Hard to know though.

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The dialect I use is Cork Irish.
Ar sgáth a chéile a mhairid na daoine, lag agus láidir, uasal is íseal

That’s still a weird reinterpretation of the structure to me. The origin of the likes of fear is ea é is exactly fear, is ea é with a pause (‘a man: he is it’, ie. ‘he is a man’) – with the predicate topicalized (while just ea referred back to it in the focus), in Old Irish law texts this structure is sometimes used when introducing new topic and immediately doing a “reverse” definition – saying who/what is this new thing that’s under discussion.

Since beagán is indefinite, it doesn’t need any pronoun when it’s the predicate, so the is ea beagán part looks very much like beagán is the subject and the topic here, not the predicate and focus.

But I guess it kinda works here the way it used to work in OIr. fáltas: a small portion is this thing, is an example of it?

Thank you. A lot of sentences in CFBB are hard to interpret as they all lack any context at all.

It's not as such a formal interpretation of this structure. It's more that I think parts of CFBB are written in sentence fragments, like somebody taking notes.

People do occasionally say things like "Citreon, 'sea mótar, cairt go bhfuil.....". My experience is that most native speakers don't perceive the "ea" as a pronoun. More that there is a word "sea".
It kind of falls in with things like "Tuigiú an mótar". Just an odd phrase that doesn't fit with the grammar or:
"N'fheadar tháinig sé óm baile"

Parts of CFBB seem to me to be written in this sort of colloquial, almost ungrammatical, type of talk. Hard to be sure though.

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The dialect I use is Cork Irish.
Ar sgáth a chéile a mhairid na daoine, lag agus láidir, uasal is íseal