Arkatreides we need you!

Ok: Seleucids can train Pezhetairoi in Alexandreia, Antiocheia, Seleukeia, Baktra, Pella, perhaps Byzantion (former 0.8 could, but I'm not there yet).
Ptolemaioi: Alexandreia, and perhaps some Greek Mainland city such as Pella.
Baktria: Baktra, and pehaps Seleukeia (never played Baktria yet - I keep it in reserve...)
Makedonia: Pella... others?

Now look here: save for Gabai, Prophthasia, Alexandreia-Ariana, Charax, and Sardis every Seleukid starting settlement can train Klerouchikoi. And given that they are fairly reliable and that they are your best option in the remote provinces...