I would like to suggest several unique buildings:
A. Guard posts along trade routs that will increase trade and the productivity of the resource- in the incense road (I visit often the remains of those posts, built specially by Rome for the purpose of protecting trade). As well as other obvious trade routs, it could be built in Hadrian's wall as well.
B. The Acropolis at Scythopolis.
C. The Messada fortress (that stood years of Roman siege).
D. Petra and other Nabatean cities (will Nabatea be it's own faction?)
E. The Corinthian railway, is built already & increases trade.
F.
HaNamal WeHa'Homot Sel Qarthadast
HaMiqdasim Sel Ba'al-Hammon WeAstarot
Mitsbat HaPilaenim
(from the description in the first page)
These are written in modern day Hebrew, and in a bad way, too

.
Did the Carthaginian language perish so that we can't use that?
Can't Greek be used, or at least the phrasing fixed?
G.
To Hieron en tois Hierosolymois
This is a Jewish icon, and deserves to be called by it's Hebrew name rather than it's Greek name.
Its בית המקדש, or Beit HaMikdash.
Literally house of the temple.
If you need help finding decent pictures of it or building a 3d model for the strat map, I'm glad to help.
Cheers,
Evb.