Whenever I tried giving them cities as gifts, they literally ignore them and not build anything or recruit any units there until the city revolts or some other faction captures it.

Bribing is not a very practical option after 1.2. and even if you do bribe invading armies, the seleucids would still not be aggressive and would invade anyone.

I was wondering if changing any of the faction traits would help, like Caesar/ Napoleon/Stalin or the other ones like Smith/Bureauocrat/Religious. Any ideas on that?