Decoding the San Millán Manuscript

A tricky decoding job with the San Millán stemma seems almost complete, thanks to Brepols and their Library of Latin Texts (LLTA), an online database of Latin. Here is an image of the text:
My first transcription of this gloss about the secular city built by Cain turned out to be nonsense, but I was fortunate to find that the bulk of the text was simply borrowed from a theological exposition by Isidore of Seville, the Mysticorum expositiones sacramentorum seu Quaestiones in Uetus Testamentum. This is easily found in the LLTA: Quid ergo sibi per figuram vult, quod impiorum progenies civitatem in ipsa mundi origine construxit? nisi quod noveris impios in hac vita esse fundatos, sanctos vero hospites esse et peregrinos. Unde et Abel tanquam peregrinus in terris, id est, populus Christianus non condidit civitatem. Superna enim est sanctorum civitas (In Genesim, 6).
That allows us to transcribe the script as follows: Primus ante diluvium Cain civitatem Enoch nomine filii sui in India condidit quam urbem ex sola sua posteritate in plevit, quod sibi vult, quod impiorum progenies civitatem in ipsa mundi origine construxit? nisi quod noveris impios in hac vita esse fundatos, sanctos vero hospites esse et peregrinos. Unde et Abel tamquam peregrinus in terra populus Christianus non condidit civitatem; superna enim est sanctorum civitas.
As a result we can draft the following abbreviations key, which is useful for decoding the entire manuscript, including the Ordo Annorum:
2id = quid
s with a spike over it = sibi?
qd+ = quod
p with a downwards hook at the left = pro
9 = con
n with a rightwards hook above it = nisi
nov+is = noveris
ee with a downwards hook above = esse
sc+os = sanctos
u with a circle over it = vero
p with a straight stroke through the descender = per, with e = pere
g with a top right cantilever and a rightwards hook above = gri (cf. nisi)
vn with a line over the n = unde
qm with a kind of W over and between them = quam
9 on the shoulder at the right = -us
t+ra = terra
ppls = populus
xianus = Christianus
e with a line over it = est
LLTA also indicates that Isidore lifted the latter part of the text from Augustine, De Civitate Dei 15.1: scriptum est itaque de Cain, quod condiderit ciuitatem; Abel autem tamquam peregrinus non condidit; superna est enim sanctorum ciuitas.
In other parts of the same codex we have seen:
c with a spike over it = cri
p with a spike over it = pri
scdam where d ascender has a stroke throught it = secundam